Earthquakes of the American Continents

THE student has often to regret that the aboriginal peoples of the American continents left no records which tell us anything concerning their physical history. The convulsions which affected these lands before the beginning of the sixteenth century, their floods, their earthquakes, and volcanic eruptions, must remain forever unknown to us, except where the antiquarian may be able to find some faint trace of them in the myths and traditions of the perishing races of the New World. It would not be profitable, in an investigation requiring that the information which it seeks should be accurate, to endeavor to unravel those puzzling traditions wherein the impression made by some great accident of nature is mingled with the effects of centuries of superstition. The only human record of the convulsions of the New World which can serve our purpose begins with the Spanish colonization, about three centuries and a half ago, and thus covers only about one tenth of the time which is contained in the chronicles of the Old World. Though comparatively brief, this time has been long enough to have given us a formidable chapter of accidents exceedingly destructive to life and property, potent in their influence on the development of the peoples subjected to their action, and very instructive to the naturalist who seeks in these convulsions an explanation of the forces which affected the surface of the earth before man became a witness of their action.

Although we have no authentic record of any earthquakes before the Spanish conquest, we may safely infer that the aborigines of Mexico and South America were as much exposed to these convulsions as their successors have been. The style of the structures erected by the ancient Mexicans and Peruvians is as well suited for the resistance of earthquake shocks as that of modern fortifications for the protection of their occupants against projectiles. Buildings chiefly of one story, with walls of the most massive character, — loftier edifices arranged as terraced pyramids, — secured features admirably fitted to insure permanence on an unstable soil. With an architectural skill apparently sufficient to have produced any of the simple reliefs, such as the tower, spire, or obelisk, these nations seem never to have constructed any edifices of that nature. It may be answered that a people as little exposed to earthquakes as the Egyptians built in the same stable manner, and that another in one of the most frequentlyshaken regions of the earth, the Calabrians, have not learned the simple lesson which it might be supposed would have been taught them by their long experience. It cannot be denied that the objection has weight; but the Egyptians raised the obelisk quite as often as the pyramid, and the Calabrians have been deterred by a spirit of religious fatalism from learning any lessons which their frequent misfortunes might have taught them. The history of architecture among all peoples leads us to believe that the desire to erect lofty structures is almost a natural instinct; and when we fail to find any trace of them among the relics of a people whose skill would have enabled them to build such edifices, we are justified in seeking in circumstances some explanation of that absence. Human edifices tend to grow upwards as much as trees ; and just as we are warranted in seeking a reason for the stunted form of the firs of Labrador, whose centuries of growth have not lifted their branches six feet above the earth, so we are justified in demanding a reason for the dwarfed character of the architectural monuments of the ancient nations of Mexico and Peru.

The continents of North and South America show but little sympathy in their earthquake movements ; it is very rarely that any shock which has affected the one has influenced the other. The southern continent has received probably nineteen twentieths of the earthquake violence which has affected the New World. These disturbances have in the main been limited to two regions : that on the west coast including the whole chain of the Andes, and the tablelands which border the range on either side; and that on the north including the mountainous country on the south shore of the Caribbean Sea, between Lake Maracaibo and the island of Trinidad near the delta of the Orinoco. Although in some cases disturbances originating in one of these areas have propagated their movements in the other region, usually the convulsions of each area have exercised no marked effect on the territory of the other. As a general rule, the convulsions of the greatest violence in South America have extended their devastating effects over a wider range than the destructive shocks of the Old World. That of Lisbon, in 1755, shook a larger part of the earth’s surface than any South American shock is known to have done ; but the area within which the shock proved very destructive was comparatively limited. The Andean earthquakes have frequently proved exceedingly destructive along a line more than a thousand miles in length, though their east-and-west extension has rarely exceeded one hundred and fifty miles. The convulsions of the northern earthquake area, bordering on the Caribbean Sea, have generally been more like the Lisbon shock in their character, — the shock moving in every direction from a centre of impulse, gradually diminishing in force on all the lines radiating from that centre. The whole of the Lesser Antilles share in these commotions, which generally originate in Venezuela. Many earthquakes— such as the several great convulsions which devastated Caraccas — have affected all the West Indies, and propagated their shocks as far as the shores of Central America. And in one case, at least, — that of the earthquake of 1811,—there seemed to be some sympathy between the movements of the earth in the valley of the Mississippi and the disturbances which occurred on the northern coast of South America. The whole basin of the Caribbean may be regarded as belonging to one earthquake area; for, although the greater number of the shocks occurring there are local, many have been perceived throughout the basin.

When Columbus, in his third voyage, landed on the south shore of the Caribbean Sea, the Indians still preserved a tradition of a great earthquake which they said had rent asunder the shore of the continent, and formed the Gulf of Cariaco. It is scarcely to be believed that this important arm of the sea, having a length of over fifty miles and a breadth of over four or five, could have been torn off from the continent. Its northern shore is evidently a part of the coast range of mountains, and not the result of a recent geological accident. It is, however, by no means improbable that a subsidence of the shore, accompanying an earthquake movement, may have admitted the sea into an existing valley, and thus formed this sound. There seems little doubt that this widespread tradition referred to some great earthquake which had effected important changes in the coast lines of this part of the continent.

The menace of earthquake disturbance which this tradition gave has been quite fulfilled. In 1530 there came a great shock : a mountain on the shore of the Gulf of Cariaco was rent, and from the fissure there poured forth a great volume of salt-water mixed with asphaltum. A sea-wave rolled in immediately after the shock, which overwhelmed the fort and garrison at Cumana, and did great damage to the habitations of the young colony. Owing to the ravages of the white ants, we have no original records of this colony more than two centuries old, and may thus be unacquainted with many of the earlier earthquakes. In the latter part of the last century, in the years 1766, 1794, and 1797, there occurred three remarkable convulsions. The first of these destroyed Cumana, and shook the whole northern shore of South America: such great disturbances of the surface of the soil took place that the ground was said to have moved like a boiling liquid. The extreme violence is attested by the fact that the Indians, not unaccustomed to such accidents, celebrated by feasts the approaching destruction and regeneration of the world. The shock of 1794, though violent, did not prove destructive enough to merit especial mention.

Three years later, however, in 1797, there occurred an earthquake which entirely overwhelmed the city of Cumana, killing a large part of its inhabitants. Though terrible in its intensity, this earthquake seems to have been confined to a very small area. The shock and the sound which accompanied it were like those which would have been produced by springing a mine beneath the city. Humboldt states that half an hour before the shock a strong smell of sulphur was perceived, and that at the same time flames appeared on the banks of the river Manzanares and in the Gulf of Cariaco.

Flames rising from the ground are not uncommon phenomena in this portion of the continent, and are not necessarily connected with earthquakes. The first of the many recorded changes produced by earthquakes on the shore line of South America was effected by this shock. Some slight alterations in the topography of the shoals near the entrance to the harbor of Cumana were observed.

The great crescent of islands which extends from near the mouth of the Orinoco to Cuba, — a distance of over two thousand miles, — has been throughout more or less subject to earthquakes. All portions of this great archipelago have not however been equally exposed to their ravages. The largest of the islands, Cuba, has enjoyed comparative immunity, while its neighbor Jamaica has suffered from many destructive convulsions. The former of these islands is, strictly speaking, outside of the basin of the Caribbean, and therefore removed from the sphere of operations of the earthquakes originating beneath that sea.

Jamaica was the first of the Antilles to suffer from earthquakes. In 1667 the island was shaken from the centre to the sea. Great masses of rock were torn from the mountains, but, the population being small, the destruction of life was not great. On the 1st of March, 1687, came the second memorable shock. The earth appeared to rise and fall like waves of the sea, and all the buildings on the island were much damaged. Vessels in the harbor of Port Royal were very singularly shaken, many of them being much injured by the violent concussion which was propagated through the water. Five years later, in 1692, came the greatest earthquake, probably, which has ever visited the island. It occurred on the morning of the 7th of June, between eleven o’clock and noon. Three fourths of the houses in the capital town of Port Royal were thrown down, killing three thousand of the inhabitants. A large part of the ruined city sank beneath the sea, so that ships could ride over the spot where the most substantial houses of the place had stood. The subsidence seemed to take place at the very moment of the shock. Throughout the island the effects upon the surface of the earth were very great. At one point a tract of land of more than one thousand acres sank beneath the sea. The reports of the shock by eye-witnesses repeat the often-doubted assertion that fissures opened and closed as the shocks passed through the earth. In one of these chasms it is stated that an inhabitant of the island, Louis Gelday, was swallowed up, but ejected uninjured by the next movement of the earth, an instant after.

As in most great convulsions of this nature, the principal shock was succeeded by a long-continued series of movements of a slight character. This trembling of the earth continued until the volcanic eruption at St. Kitts, which occurred some weeks afterwards, quieted the subterranean disturbance. Several times since the great shock of 1692, severe earthquakes have visited Jamaica. Those which occurred in 1794, 1812, and 1834 were the most disastrous, all proving very destructive to life and property. The distribution of earthquake shocks throughout the other parts of the Caribbean Islands is quite peculiar, some of the islands having enjoyed a happy immunity from destructive shocks ever since their settlement, others having been even more unfortunate than Jamaica. Cuba, for instance, has been unharmed by any great accident of this kind, though from time to time particular parts of it have been considerably shaken : the most destructive of these local shocks was that which visited St. Jago and the region thereabouts. Hayti and Porto Rico have been equally fortunate in escaping the severest effects of the earthquake violence which has proved so very disastrous to the neighboring islands. It is among the Lesser Antilles, which form the remarkable band of islands stretching from Hayti to Trinidad, that we find the most destructive results of earthquake action. In St. Croix and St. Thomas the melancholy history of a long struggle of northern energy with convulsions of earth and air has apparently been ended by a series of hurricanes and earthquakes which have quite destroyed the prosperity of the islands. The incidents of these harrowing calamities are too fresh in the mind of the public to require mention here. The island of Tortola, which was swept over during this convulsion by an earthquake wave, was rent asunder by the earthquake of 1785, a new island being formed. Our accounts of this remarkable event are not sufficiently detailed to enable us to form an idea of the precise character of the movement which brought the separation about. Owing to the fact that most of the other islands of the Lesser Antilles were settled at a much later date than those above mentioned, we know less of their earthquake history. With the exception of Barbadoes, which lies very much to the eastward of the main chain of islands, and is thus,like Cuba, beyond the region of the greatest violence, they all have been sharers in the disturbances which have affected this basin ; Martinique and Guadeloupe having been the most unfortunate.

The northern shore of South America was again visited by a great convulsion in the year 1812, when, at about four o'clock on the 26th of March, after a very hot day, there came a great shock which affected the whole of the provinces of Venezuela, Maracaibo, and Varinas. This earthquake was the most extensive in its range and the most destructive in its effects, of any which have ever occurred on this shore. The intensity of the shock varied very much, however, at different points ; in some places the ground is said to have resembled a boiling liquid, great masses of rock were detached from the mountains at many different places, and at Valencia an enormous volume of muddy water burst forth. About one year earlier the volcano of St. Vincent, which had been at rest for about a century, began to be again active ; frequent shocks announced the increased disturbance in the region beneath the mountain; one month after the great earthquake the eruption began by an ejection of cinders, and on the 30th of April the lava broke forth and ran down into the sea.

The earthquakes which have desolated the north and east shores of the Caribbean Sea have been equalled in intensity by those which have affected its western coast. The earthquakes of Central America have been quite as terribly destructive as any of those before mentioned ; though, as they acted upon a less civilized and less thickly settled country, the records of their action are not so complete. Soon after the settlement of the country, in 1565, there occurred a shock of considerable severity in connection with an outbreak of the volcano of Paraya. In 1586 the city of Guatemala was ruined: this, like the preceding shock, was followed by a volcanic eruption, the outlet for the pent-up force being in this case the volcano of Fuego, near the devastated city. In 1798 and 1820 the city was again very much shaken and the region thereabouts much affected by severe earthquakes. The last very destructive shock occurred in September, 1841. By this convulsion all the cities and towns of Costa Rica were ruined, and throughout a great part of this region not a single building was left standing. Unlike most earthquakes of this region, which have usually extended their disturbances very little beyond the territory known as Central America, this shock was felt all over Mexico and a considerable part of the United States. Yucatan is included in the seismic area of Central America, being affected, though in a less degree than Guatemala, by the shocks which disturb that area.

Thus it is seen that the shores of the Caribbean Sea are even more unfortunate than the borders of the Mediterranean. Excepting the island of Cuba, which, as said before, belongs rather to the Gulf of Mexico than to the Caribbean basin, every part of its shores is grievously affected by frequent visitations of the chief of destroying agents. No portion of the earth’s surface is so fortunate in every geographical feature as this beautiful sea. Girdled by the most fertile lands of the world, which in their varied surface afford many of the best features of temperate climates beneath a torrid sun, it would seem as if it were especially designed to rear great and varied peoples along its shores. The long crescent of islands which separates it from the broad waters of the Atlantic abounds in harbors to an extent quite unusual in tropical countries, and seems in every regard well fitted to be the cradle of a race of mariners. At its gates open the three great rivers of the Americas, the Mississippi, the Orinoco, and the Amazon ; through its waters lies the great natural highway from the peoples of the Atlantic to those of the lands which border on the Pacific Ocean. Yet all these advantages seem powerless to develop the races dwelling on its shores. Three centuries’ existence has given some increase of numbers, but not one particle of advance ; indeed, at many points the observer is forced to acknowledge that the Spanish colonists have sunk below the level occupied by their fathers. Despite the great natural advantages of the region they inhabit, they have become neither mariners nor merchants. Despite a climate which from all analogy we should judge favorable to the development of some intellectual brilliancy, if no great amount of intellectual force, there has not been a single name of any celebrity either in art or literature. Before we attribute the failure of the colonies of the Caribbean to peculiarities of race, or lay the whole blame upon the influences of climate, it is but just to consider whether the instability of the land may not have contributed to oppose the highest development in that region.

The western coast of South America, from the Isthmus of Panama to Patagonia, has been in a condition of almost incessant movement since the time of the Spanish settlement. The frightful convulsions of a few months ago, which by earthquake shocks and oceanic waves devastated nearly twelve hundred miles of this coast, sacrificing over fifty thousand lives, are still fresh in the public mind. Yet this terrible destruction of life and property has recurred so often within the past three centuries that it has ceased to be reckoned by the people as an accident out of the course of nature, and is looked upon as a phenomenon as much to be expected as a thunder-storm in other lands. Although only about three centuries have elapsed since our chronicles of the earthquakes on this shore began, they afford us an appalling list of convulsions which have in quick succession devastated a greater or less portion of the states bordering on the Pacific. The first recorded shock occurred in 1570. It seems to have been extremely violent, although the limited extent of the Spanish settlements at that time made the observations very imperfect. We learn, however, that at St. Jago, in Chili, great landslips and falls of rock took place, and that a great earthquake wave rolled upon the land. Twelve years later Arequipa was almost ruined by the first of the many shocks from which it was to suffer in the succeeding centuries.

In 1586 another great shock ravaged the shore for a distance of six hundred miles, concentrating its force in the neighborhood of Lima ; with this shock came a sea-wave fourteen fathoms high, which inundated the country for six miles from the shore. In 1600 there was an earthquake at Arequipa, succeeded by a great darkness and rain of ashes for twenty days. 1604, 1647, and 1657 brought great and destructive earthquakes, but there seems not to have been enough of an exceptional character to warrant especial mention. In 1697 Lima was again greatly damaged, and the next year the summit of the volcanic mountain of Carguarazo fell in during an earthquake, and a great torrent of mud and water which burst forth did much to complete the ruin begun by the shock. This torrent doubtless had its source in one of those crater lakes so common in most volcanic countries, the bounds of which were broken by the fall of the mountain. The towns of Hambato and Hacatunga were completely ruined by this shock. The years 1716 and 17-20 brought devastating shocks in Peru and Ecuador, greatly damaging Lima and Arequipa. In 1736 the town of Hacatunga, rebuilt after the earthquake of 1697, was again laid in ruins. The territory suffered a still greater blow from the earthquake of October 28, 1746. The first shock was the most severe, but over two hundred occurred within the ensuing twenty-four hours. Lima and Callao were much injured by the earthquake, and the great wave, over eighty feet high, which rolled in upon the shore, completed the destruction to the latter city, and brought ruin to four other harbors on the coast. During the same disturbance, four volcanoes in this part of the Andes poured forth torrents of water from their fissured sides. These floods came doubtless, as did that which escaped from the crater of Carguarazo in 1697, from the great cavities left by the retreating lava in the depths of the mountains.

The most destructive earthquake of the century, indeed one of the most calamitous shocks known to have visited any portion of the earth, was that which shook a large part of the Andean chain on the morning of the 4th of February, 1797. The region most affected lay within the territories of Peru and Ecuador ; over a large part of both of these stales the destruction was terrible. This shock is frequently mentioned in history as the earthquake of Riobamba, a city — one of many ruined by the shock — which owes its prominence, not so much to the greater severity of the earthquake there, as to the fact that the effects of the shock at that point were attentively examined by Humboldt when he visited the spot, a few years after the calamity. The observations of the illustrious traveller showed that the intensity of the movement was unparalleled in the history of earthquake shocks. Among other strange results, there is reason to believe that bodies of men were thrown through the air to the summit of a hill, one hundred feet above the level of the city, and several hundred feet distant therefrom. The shock was accompanied, or rather succeeded, by a terrible sound, which, however, was not heard over all the region affected. In the region of greatest disturbance every dwelling was overthrown, and many houses were buried beneath the masses which were shaken from the mountains. Over forty thousand people perished. Around Tunguragua the earth poured from fissures formed by the shock many great streams of water. Flames and suffocating vapors burst forth from the surface of the lake of Quilotoa, in the region of Hacatunga, destroying the herds of cattle feeding on its banks. In 1819 Copiapo was ruined by a succession ot shocks, which occurred between the 3d and the 11th of March. Again, in 1822 and 1826, much damage was done to the same city by severe shocks. The next general earthquake in the Andean region occurred on the 30th ot May, 1827. The area of greatest disturbance was in and about Lima. The city was ruined, with great loss of life. The year afterwards, on the 30th of March, came another shock, throwing down most of the houses which had withstood the movement of the preceding year. Valparaiso and Santiago, in Chili, were visited by very severe shocks in October, 1829 : much damage was done to life and property. On the 20th of February of the succeeding year, after one or two premonitory movements, there came three great shocks in quick succession, which overthrew the cities of Concepcion, Salacuhuano, and Chillan, as well as many smaller towns. After this shock the shore line was found to be permanently elevated along several hundred miles of the coast. The uplift was from one to ten feet, but at some points a gradual subsidence reduced it one half. This shock, like most which have desolated this shore, seems to have originated some distance seaward of the shore line. This was indicated by the successive waves of vast height which rolled in upon the shore. Other evidences of the submarine origin of the shock were noticed. Two columns of thick smoke were observed to issue from the sea, and at the point where they came forth the water retained for some time a whirling motion, as if the waves were pouring into some great cavity. Another shock of almost equal intensity visited the same shore in 1837. Valdivia was ruined, and many other towns much damaged. The shore is said to have been strewn with uprooted trees, and the bottom of the sea among the islands of

the Chonos Archipelago was permanently raised more than eight feet. A whale-ship some miles off the coast was so violently shaken that she lost her masts. From that date to 1851, this part of the South American coast enjoyed a comparative immunity from earthquakes of destructive force. In 1851 Valparaiso had four hundred of its houses ruined. In 1859 Quito lost five thousand of its inhabitants, and immense damage was done to the city by a severe shock. The convulsions which have since shaken the southern continent are so well remembered as to require no description here.

Our glance over the history of the South American earthquakes has shown us that quite one half of the coast line of the continent is subject to earthquakes of the most destructive character. Those unfortunate countries include the fairest portion of the continent,— that which nature has favored the most with superb scenery, varied and generally healthful climate, and rich stores of mineral wealth. There seems not much to be hoped for the future there, at least until the disturbing forces sink to rest ; for how can political stability, continuous effort, or any other result of an advanced civilization be expected, where the land is as treacherous as the sea, and the forces of nature seem man’s natural enemies ? If the younger of our twin continents is ever to bear great and prosperous peoples, it is to be feared that we must look for their development, not among the grand mountains on the north and west shores, or the richly endowed table-lands which lie on the flanks of these, but on the low ridges and vast plains of the eastern shore, where, though the inhabitants are exposed to the unmitigated heat of a torrid sun, they still have the first condition of prosperity assured to them in the stability of the soil beneath their feet. The forces which build up the continents have not ceased their work in South America: they seem to be more active there than on any other part of the earth’s surface. Man has taken possession of that land before the preparation for him was complete.

As we pass northward from the central portion of the western shore of South America, we find the intensity of the seismic energy steadily decreasing. The earthquake record of Mexico is much less extensive than that of any equally large portion of the Andean region. The first shock recorded by the settlers of Mexico was in 1542; all valuable details concerning it are wanting. In 1575 the district of San Salvador was visited by a disastrous shock. 1577, 1593, 1625. and 1656 brought destructive convulsions.We have no good descriptions of the phenomena connected with these earthquakes, so that it is not worth while to study them in detail. On the 24th of March, 1697, began that series of frequently recurring earthquakes of the greatest intensity which have so often desolated the region about Acapulco. Like most of the movements of succeeding years, this shock was accompanied by a loud subterranean sound like the firing of volleys of cannon, which added much to the terror produced by the convulsion. On the 14th of March, 1787, the city was the second time destroyed. There seems to have been also a great change in the level of the shore line, but we are not told whether or not it was permanent. In the September succeeding, the city of Mexico was much injured by an earthquake. Acapulco was once more shaken into ruins in 1799. The city of Mexico was again greatly damaged by an earthquake which occurred on the 6th of March, 1800. This earthquake is interesting inasmuch as it presented those peculiarities of movement which are commonly believed by the people of earthquake countries to indicate a rotary movement of the ground in the affected region. The shock of 1820, though not very severe at Acapulco, was nevertheless attended by a most extraordinary movement of the sea. The water at first retired slowly to a considerable distance from the land. After two hours it returned, not in a great wave as is usually the case, but gradually, like a fast-coming tide, rising many feet above its previous level,— so high, indeed, as to cover a large part of the city. This movement was repeated two or three times before the sea returned to its original level. At the time of the next great shock, on the 6th of January, 1837, the city was completely ruined, but was spared the visitation of the sea-waves.

On the 20th of the same month the volcano of Cosiguina began an eruption, accompanied by a succession of violent shocks, which desolated the country for a distance of twenty leagues from the crater. There is probably no case on record where the destructive effect of shocks accompanying a volcanic eruption were more wide-spread and complete. Again in 1837, a severe and long - continued series of shocks was felt at Acapulco. Some accounts state that the vibrating movement continued for more than a month.

There seems to be even as little connection existing between the earthquakes of Mexico and those of the rest of North America as we have found to exist between the shocks which affect the Caribbean area and those of the northern part of our own continent. Only one or two of the Mexican disturbances have propagated their movements as far as the valley of the Mississippi.

The earthquake shocks of our own continent, though fortunately somewhat less numerous than those of the twin continent to the southward, are yet sufficient to enable us, in our observation of their distribution, to perceive three distinct areas of disturbance, each so clearly limited that we may say the shocks of each are from an independent source of movement. These areas correspond with the most general topographical divisions of the continent, the valley of the Mississippi constituting one, and the others being to the east and west of the mountain chains which separate this basin from the sea borders. We have a number of shocks recorded from each of these areas, yet it is doubtful whether, with a single exception, any of these disturbances has been felt outside of the area in which it originated.

We are as yet too ignorant of the history of the disturbances which may have taken place during the last century in the region known as British America, to determine whether it is to be regarded as a part of the Mississippi area, or whether its disturbances are limited to its own extent. The northern portion of the Pacific coast of our continent is almost equally unknown to us. A number of observations on the earthquakes of Alaska render it probable that that region either constitutes an independent area or participates in the movements of the neighboring Asiatic shore. The region to the southward, between Alaska and the United States, is so little known to us that we can only conjecture that it is likely to participate in the movements which affect the shores farther to the south.

The general correlation of the seats of the greatest seismic energy on the continent of North America is quite peculiar. At each corner of the great triangle which the continent forms, — in Central America, Alaska, and Iceland, — we have a limited region where everything betokens great activity of those forces which, operating beneath the crust, are manifested at the surface by earthquake shocks and volcanic eruptions. Over the remainder of the surface of North America we have no indications of existing volcanic activity, the only manifestations of internal force being in the shape of earthquake shocks. There can be no doubt that at a time geologically recent, — during the later part of the tertiary period, - the Pacific coast and a large part of the Rocky Mountain region was the seat of volcanic and probably of earthquake energy much more intense than now exists in the continuation of these mountains on the southern continent. The most extensive areas of volcanic rock known to exist on the surface of the earth are to be found in Oregon and the mountains to the southward of that State. The volcanic district of the Columbia River is as large as the Empire of France; and over its whole area are scattered, to the depth of many hundred feet, the products of the great convulsions which in this as in many other regions of volcanic activity occurred at the close of the last geological period. Earthquakes leave no such enduring evidences of their action as volcanic eruptions, so that we cannot prove that during the period of disturbance this companion force of volcanic energy was very intense in its action ; but from what we know of the relation of the two manifestations of internal activity, there can be little doubt that this was also a period of frequent and violent earthquakes.

It seems by no means impossible that man may have been a witness to those prodigious manifestations of seismic force, far transcending any effects of internal activity which have been seen by historic peoples. If the remains of the prehistoric man from California, now in the hands of Professor J. D. Whitney, be really from the bed where they are said to have been found, then our race was certainly represented on that portion of the Pacific shore long before those great convulsions occurred.