GEOLOGIC time presents to the scientist one of the most difficult problems with which he has to deal. When the different diyisions into which he would divide the ages are numbered by thousands and even millions of years, the human mind is appalled at the prospect; and when the calculations of different geologists vary by hundreds of thousands of years, the lay mind can not help growing somewhat credulous] and at times be tempted to discard the whole mass of scientific data relating to the subject.
Niagara River forms one of the best, if not the best, means of studying the lapse of time since the Tee Age. Finding, as students do here, the best material in existence for this study, leads to exhaustive scientific analysis of every clue presented by the Cataract and the deep Gorge it has cut for itself through the solid lime rock and Niagara shale forming its bed.
We are prone to look upon the great wonders of the world as destined to last as long as the earth itself. We do not realise that the mountains, miles in height, are slowly crumbling before our eyes, or realise that the rivers are carrying them slowly toward the sea, filling the lakes and lower portions of land along their courses. These slow but ceaseless forces are continually at work, reducing the surface of the earth to that of a level plain and at the same time depriving the land of its lakes by filling their depressions with silt. The winds and the waters, together with the wearing power effected by frost, are the forces struggling at this great levelling task. The work is partly done; in many of the older regions the lakes and elevations have almost entirely disappeared. Other parts of the land are comparatively new; and it is here that one sees the rough mountain or the deep canyon of the river; sufficient time not having elapsed to wear away the elevation in the one case nor the steep banks in the other.
One needs but to look at a relief map of the Niagara district to note the Falls and the outline of the Gorge to see at once that this is a comparatively new region or, at least, that the formative forces which gave it its present characteristics were at the highest stage of their career when the lands to the south had almost reached their present stage. These facts can be observed by any person visiting the Niagara district ; it does not require a geologist to trace roughly their course.
Questions naturally arise in calculating the age of Niagara. If, as all the facts seem to indicate, this river has had a very recent beginning, what then did it do before it occupied its present course? What will be its final destiny? What will happen when it has worn its Gorge back to Lake Erie? Or will the general level of the land be so changed that the Falls will never recede to the lake? The last and most important of all is: How long has it taken the Falls to grind out the Gorge thus far? This latter question, viewed in its relation to the first one, forms the basis of the present chapter. The great work of the Cataract is going on before our very eyes. The history of this great river is working itself out at the height of its glory] in an age when all can behold. It is the more interesting since it is the only example of the kind known. One can easily look back to the time when the water flowed along the top of the plateau to Lewiston and the Falls were situated at that point. This date, of course, witnessed the birth of Niagara, for, wherever the waters flowed before] they could not have taken this course before the Falls began their work. The day that witnessed the beginning of the one witnessed also the birth of the other. Likewise one can not help looking forward to the day when Niagara shall have accomplished its work, when its waters shall have completely ground the plateau in two, and so drained Lake Erie to its bottom.
What did the waters of the lakes do before the Niagara began its history? How long has it been at its present work? These are the questions interesting to every one; and by far more interesting to one who is making a study of the formative forces now contributing, and which have contributed to bring about the present characteristics of surface structure. A few important facts exist, and these now are beyond doubt, upon which rest the inferences concerning the age of the Falls. In ancient times the waters of Lake Erie did not find an outlet through Niagara River, so there was no channel ready made for the river when it began its present course. Even after the beginning of the river the upper lakes, Huron, Michigan, and Superior, did not discharge their waters through Niagara Until comparatively recent times only the waters from Lake Erie discharged through this channel and therefore for many ages only a small fraction of the present volume could possibly have been at work on the Falls.
The striking features of the Gorge are modern, and have been very little affected by those agencies which are continually moulding the contours of land surfaces. The inclination of the river’s bed has varied greatly with the ages, due to gradual uplifting or depressing of the earth’s crust; consequently the current has varied greatly in velocity with these changes. A calculation of the work done by the river during each epoch of its history is indeed fraught with many difficulties. Much investigation, however, has been made along this line and with a rather satisfactory degree of success.
Niagara appears to have had a life peculiar to itself; but what is unique in its history, is the presentation of characteristics which in the case of other rivers have long since passed away. Rivers, and especially very large ones, appeal to us as “unchangeable as the hills themselves ” ; but the truth is, that the very hills and mountains are changing as a result of the forces exerted by water. Niagara, as viewed by the geologist.] is unique, not on account of its having a different history than any other river, but for the reason that it had a more recent beginning. The calculation of the life of such a stream is interesting in itself, besides the other great questions settled by the solution of such a problem as the probable number of years that the river shall exist in its present form in, the centuries which have elapsed since the ice retreated from this region, and the ascertaining of certain facts concerning the antiquity of man. In order to make a thorough study of these topics, one must take a view of the relief features of the Niagara region, and make a careful review of what conditions existed at the time that this district was covered by the great ice sheet, together with the changes effected during the retreat of the Great Glacier to the north.
Niagara River has its origin in the eastern end of Lake Erie, about three hundred feet higher than the surface of Lake Ontario. Passing from Erie to the last-mentioned lake the descent is not gradual, but one finds a gently rolling plain with almost no slope for nineteen miles until almost at the very shore of Lake Ontario, where almost unexpectedly one comes upon a high precipice from which a magnificent view of the lower lake may be gained, only a narrow strip of beach intervening. This cliff is called by geologists the Niagara escarpment.
When the river leaves Lake Erie its waters are interfered with by a low ledge of rock running across its channel. After passing this its waters meet no more troublesome obstructions until coming to the head of Goat Island. The river can scarcely be said to have a valley. One is reminded more of an arm of the lake extending out over this region. The country from Lake Erie to near the head of the Rapids above the Falls rests on a stratum of soft rock; from the Falls northward the underlying stratum is formed by a ledge of hard limestone, and beneath this a shale and two thin strata of sandstone. By the descent of the Rapids and the Falls, the waters are dropped two hundred feet, and thence through the Gorge they rush along at an appalling rate over the descent, through the Whirlpool and on to Queenston for a distance of seven miles. From this city to the lake there is little fall and so only a moderate current.
The deep, narrow gorge extending from the Falls to Lewiston is the especial subject of study to the geologist. This canyon is scarcely a quarter of a mile wide] varying little in the distance from cliff to cliff throughout most of its course. This chasm opens up before the student with almost appalling suddenness, while travelling over an otherwise regular plain. Its walls are so precipitous that few opportunities are offered for scaling them; and their height from the bottom of the river varies from two hundred to five hundred feet. An examination of both sides of the Gorge shows the same order in the layers of rock and shale on comparatively the same level, with the same thickness of each corresponding stratum. If a superstitious person had come unexpectedly upon this gigantic fissure ages ago, he might easily have imagined it to have been the work of some mighty mythological hero; but the modern scientist has reached a much better, as well as a much more satisfactory conclusion, namely, that this immense cleft, has been sawed by the force of the water, from a structure whose features were continuous, as is manifest by the similarity of the exposed strata on the two sides of the stream. To be convinced of the fact that the Falls are gradually receding, it is only necessary to observe them closely for a few years. The breaking away of an immense mass of rock previously described is one of the recent events in the history of the river. This establishes the fact that the Gorge is growing longer from its northern end through the agency of the waterfall.
These facts show us the river working at a monstrous task. Its work is only partly done. Two questions come to us almost immediately: When this work is done what will it do? and, What did it do before its present work begun? The waters of Lake Erie could never have flowed to Lake Ontario without wearing away at the Gorge we now see. The birth of the river and the cutting of the canyon were simultaneous. Of this much we are assured.
A superficial study of a map of North America will show at once a great difference in the northern and the southern sections. From the region of the Great Lakes northward the district is one continuation of lakes, ponds, swamps, and rivers with many rapids. South of the Ohio there are few lakes, and the rivers flow on with almost unbroken courses. Here is a region much older than that to the north; and its waters have had ages more in which to mould down elevations and fill up depressions. The cause of this difference in the characteristics of the streams of the North and those of the South is to be explained by the great Ice Age. As far as we now know there may have been little difference in relief forms between the two sections before the encroachment of the ice. During the glacial epoch the whole northern part of the continent was covered with a thick ice sheet, which was continually renewed at the north, and as continually drifted slowly in a general southerly direction. As this heavy ice cap passed over the surface, it acted somewhat like a river in its erosive power, only working much greater changes. It not only picked up loose particles, but also scoured and wore away solid rocks along its bed. Thus the whole configuration of the country was changed.
At the southern terminal of the glacier, where it ended in the ocean, the ice broke away in large bergs, as in the northern seas to-day; but where the advancing ice met the warmer climate on land, it was melted and thus deposited at its terminal all the material it carried. The eroding power of this ice sheet, together with the deposit of its materials on melting, brought about a great change in the configuration of the country. Many old valleys were obliterated, while a number of new ones were carved. As the ice retreated northward with the change of climate, new lakes and rivers were formed. Many times the streams escaping from the lower level of lakes were forced to find an entirely new course, and so to carve a new channel of their own. The region of the Great Lakes and the Niagara River is no exception to this rule; and it is with the ending of the Ice Age that the history of the river begins.
A glance at a map shows a low range of hills or rather a gentle swell in the land surface forming the watershed between the lakes and the streams flowing to the south. At the time of the farthest southerly extension of the glacier it reached beyond this elevation; and its waters were discharged into the rivers flowing to the south. When the southern terminal had retreated to the north of this divide, but still blocked all outlet to the north or east, there was doubtless a number of lakes here discharging their waters across the present low watershed to the south. Some of these ancient valleys can still be traced for long distances of their course. These lakes passed through their varying history as those of to-day, their surface troubled by wind and storm and their waves leaving indelible carvings upon their shores.
One of these lakes occupied what is now the western end of Lake Erie, shortly after the ice front had passed to the north of the watershed mentioned. There are still very definite markings which show that its waters were discharged across the divide by a channel into the present Wabash River and thence into the Ohio. This channel can be traced throughout most of its course very easily. There are at least four distinct shore lines preserved to us, which show four successive levels of the lake as it reached lower outlets before the Niagara River was born. All of these old shore lines can be traced throughout most of their courses.
As the ice continued to retreat, next we notice the greatest change in elevation of the surface of the water. The ice front finally passed to the north of the present Mohawk River, thus allowing the waters to escape by that outlet, and, as a consequence, lowering the surface of the lakes by over five hundred feet. This drained a great extent of land and dropped the surface of Ontario far below the present level of the Niagara escarpment. Then for the first time the Niagara began to flow, and its Falls began their work. Immediately upon the formation of this new, lower lake it began the work of leaving its history carved upon the rocks, sands, and gravels which formed its shores. Its first ancient beach is more easily traced for almost its entire course than any of the other old levels. It does not even take the trained eye of the scientist to see its unmistakable history written in the sands. The earliest western travellers describe the Ridge Road running along this old, deserted beach as showing unmistakable signs of having been an ancient shore line of the lake.
In following the course of this old shore line a gradual slope is noticed, and if this was a shore line, we must account for this variation in elevation, since the surface of the water is always level. The explanation is to be found in the fact that portions of the earth’s surface are gradually rising while others are as gradually sinking. On comparing the old coast line with the level of the present one, we find that the lake has gradually inclined to the south and the west. This change in elevation had its share in determining the configuration of the lake as well as the relief features of the surrounding region. The point of discharge was at Rome, New York, as long as the barrier blocked the regions north of the Adirondack Mountains. As soon as the encroaching warmth of the south had removed this barrier to the level of the Rome outlet, the water began flowing by the St. Lawrence course. True the first outlet was not the same as the present one; but it must have been many times shifted in the course of the retreat of the ice. As a result of this alternate shifting, together with the changing of the level of the lake, there are to be found the markings of numerous shore lines, some of which pass under the present level of the waters.
These different variations must of necessity have had a great effect on the work of Niagara River. When the Niagara began to flow, instead of its terminal being nearly seven miles from the escarpment, it was only between one and two miles away, and the surface of the lake was about seventy-five feet higher than now. While the outlet remained at Rome, the eastern end of the lake was continually rising, which caused the waters at the western end to rise over one hundred feet.
This placed the shore of Ontario almost at the foot of the beautiful cliff at Queenston and Lewiston. After having occupied this position for a long period, the surface of the waters again fell over two hundred feet, carving an old shore line which is now submerged. After this, various changes of level in the land and shiftings of the ice barrier caused numerous old shore lines to be faintly carved. These changes continued until the present outlet was established and the waters began to flow along the present course of the St. Lawrence.
One might think that with these changes all the variable factors of our problem have been discussed ; but these same factors also had their effect upon the upper lakes. In a study of the old markings of all the lakes of this region, it seems that the northern shores were continually rising ; this, of course, points to an occupation of a more northerly position by the lakes than at present, and also a laying bare of northern parts, and shifting of waters south, or possibly both of these changes at once.
In the most ancient system of which we can obtain an approximately definite knowledge, Lake Huron was not more than half its present size, while Georgian Bay formed the main body, connecting with Huron by a narrow strait. Michigan and Superior occupied about their present limits, but were connected with Huron by rivers rather than short straits; Erie occupied only a fraction of its present position, having no connection with Huron. The waters of the upper lakes were doubtless discharged from the eastern end of Georgian Bay, which then included Lake Nipissing, by way of the Ottawa River, into the St. Lawrence. Thus the Niagara was deprived of about seven-eighths of its present drainage area, and consequently was totally unlike its present self. There is some indication that there may have been an outlet from Georgian Bay by a more southerly route, namely, the Trent River. If this were so, the northern route must have been blocked by the ice, since the Trent Pass is much higher than the one leading from Lake Nipissing, by way of the Ottawa. These are some of the possibilities which must be taken into consideration before any sure calculation can be made as to the age of the Falls, for there must have been an epoch in the history of the river, were it short or long, during which it carried only a very small fraction of the waters which it bears at present.
Let us turn again to the gorge of the river itself. We have noted the similarity of structure of its two sides. This similarity is continuous throughout except at about half-way from Queenston to the Falls, where the river makes a turn in its course of almost ninety degrees. On the outside of this angle is the only place in the whole course where the material of the cliff changes. Here there is a break in the solid rock of the bank, which is filled with loose rock and gravel. This rift, to whatever it may be due, is of pre-glacial origin, for it is filled with the same material, the glacial drift, which covers the whole region. The cliff along Lake Ontario also presents very few breaks; but a few miles to the west of Queenston at St. Davids a broad gap is found in the otherwise unbroken wall. This gap is also filled with glacial drift. On its first discovery it was supposed to be a buried valley, and no connection with the Whirlpool was attributed to it. Later it was supposed that the break in the side of the Gorge, and the one at St. Davids, were parts of one and the same course of some pre-glacial stream. This supposition has been proven by the course having been traced through most of its distance by the wells sunk in the region. Later this interpretation of the facts found was destined to furnish further explanations. The question at once arose: How far and where did the upper course of this ancient valley extend? If it had cut across the course of the modern river, there would have been a break in the continuity of the cliff somewhere on the opposite side of the Gorge; but this can nowhere be found to be the case. The upper course of this ancient channel, therefore, must have coincided with that of the present channel. When, then, the Falls had receded to the side of the present Whirlpool, it reached a point where the greater part of its work had been performed. From here to whatever distance the upper course of the ancient river extended, the only work to do was to remove the loose gravel and boulders with which the glacier had filled its channel. This, of course, was effected much more rapidly than the wearing away of the hard limestone bed. Just what was the depth, and how far this old deserted valley extended, it is almost impossible to estimate. These changes are some of the most potent with which one must reckon in any calculation of the time since the beginning of Niagara’s history. However, some work has been done in this line; and a broad field is still open for future investigation.
At a very early date (1790), and when it was supposed by many to be almost sacrilegious to discuss the antiquity of the earth] Andrew Ellicott made an estimate of the age of the Falls by dividing the length of the Gorge by the supposed rate of recession. This gave as a result 55,000 years as the age of Niagara River. The next estimates which commanded attention were those of Bakewell and Sir Charles Lye11. Each of these men made separate estimates, but were compelled to take as the basis of their calculation the recession as given by residents of the district. Bake-well’s calculations preceded Lyell’s by several years, and resulted in ascribing to the Falls an age of 12,000 years. Lye11 found the age to be about 36,000 years. The popularity of the latter caused his estimate to be accepted for a long period; many persons undoubtedly placing more faith in his results than he himself did. This method of dividing the distance by the rate of recession would be correct if there were no variables entering into the problem, and if the rate of recession were known; but these first calculations involved errors in the rate of movement of the Falls besides making no allowance for the variations which have been mentioned above.
In order to obtain a sure means for measuring the recession of the Falls, Professor James Hall made a survey of the Horseshoe Falls in 1842, under the authority of the New York Geological Survey. This survey plotted the position of the crest of the Falls, and established monuments at the points at which the angles were taken; thus leaving lasting marks of reference to which any future survey might be referred. In 1886, Professor Woodward of the United States Geological Survey, by reference to the markings left by Hall, found the rate of recession for the period to be about five feet per annum. It would, however, be necessary to extend these observations over a long period of time, since certain periods are marked by large falls of rock. Sometimes the centre of the Falls recedes very rapidly, while at other times the centre is almost stationary and the sides show the greater action. One of the most recent calculations of the age of the Falls was made by J. W. Spencer. Having made a thorough study of the history of the river revealed in its markings, and also of the Lakes, making allowance for all the variable factors] he calculated the duration of each epoch separately; and found the age of the river to be about 32,000 years. This result is about the same as that obtained from those based upon the relative elevations of different parts of the old deserted shore lines; and another based upon the rate of the rising of the land in the Niagara district.
The many variable factors entering into the calculations so far discussed, have led to an earnest search for some means of determining the age of the river, which does not involve so many indeterminate and unknown quantities. This means of calculation, and one which seems to be much more free from unknown factors, seems to have been hit upon by Professor George Frederick Wright, whose calculations are based upon the rate of enlargement of the mouth of the river at the Niagara escarpment, where the Falls first began their existence. The cliffs at the mouth of the Gorge, as is the case with the newer portions of the river and indeed is characteristic of all canyons when first formed, were undoubtedly almost perpendicular when they were first cut by the rushing waters of the Niagara River. The mouth of the Gorge at Lewiston is of course the oldest part of the river; and if it were possible to measure the age of this part, this would surely give the date of the birth of Niagara. Immediately upon the formation of the Falls at Lewiston, the waters
began the cutting of the Gorge; and immediately upon the formation of a gorge there was set to work upon its walls the disintegrating agencies of the atmosphere, free from indeterminate variables, tending to pull down the cliffs upon each side of the stream which jealously walled it in.
This work has gone on year after year and century after century, without being affected by either the volume of the river’s waters or the shifting in the elevation of the land. The work of the atmospheric agencies in enlarging the mouth of the Gorge has had the effect of changing its shape from that of a rectangle, whose perpendicular sides were 34o feet, to a figure with a level base formed by the river, whose sides slope off at the same angle on each side. Now if it were possible to measure the rate at which this enlargement is taking place, the problem of determining the age of the river would be a more simple one.
The relative thickness of the different layers of material forming the walls of the Gorge is not the same throughout; at the escarpment at Lewiston] the summit is found to consist of a stratum of Niagara limestone, about twenty-five feet thick. Beneath this layer of lime is to be found about seventy feet of Niagara shale. The Niagara shale rests upon a twenty foot layer of hard Clinton limestone, which in turn is supported by a shale seventy feet thick. Forming the base is twenty feet of hard Medina sandstone, beneath which is another sandstone which is much softer and much more susceptible to erosion and the disintegrating forces of the atmosphere. These thick layers of shale form the part upon which the atmospheric powers exert their energies, undermining the strata composed of material which with much more effect resists the attempt of any agency to break it down. As the shale is removed from beneath the harder layers immense masses of the latter fall and form a talus along the lower part of the cliff. This in brief is the manner in which the mouth of the Gorge is growing wider.
The present width of the mouth of the Gorge at the water’s level is 770 feet. It is not likely that the river was ever any wider than now at this point, since its narrowest portion is over 600 feet, and this where the hard layer of Niagara limestone is much thicker than at the mouth. The current here is comparatively weak, so that there has been little erosion due to it. On the contrary the falling masses of sandstone and limestone have probably encroached somewhat upon the ancient margin of the stream, its weak current being unable to sweep out these obstructions which have formed an effectual protection to the bank.
The observations necessary to Dr. Wright’s calculations were taken along the line of a railroad, which, very opportunely, had been constructed along the eastern cliff. Here for a distance of about two miles the course of the road runs diagonally down the face of the cliff, descending in that distance about two hundred feet, and in its descent laying bare the layers of shale upon which the observations must be made. Along the course of the road at this point, watchmen are continually employed to remove obstructions falling down or to give warning of danger when any large masses fall. The disintegration goes on much more rapidly in wet thawing weather than at other times of the year. Often in the spring the whole force of section hands is required for several days to dispose of the material of one single fall. At the rate of one-fourth of an inch a year of waste along this cliff there ought to fall slightly over six hundred cubic yards annually for each mile where the wall is 15o feet high. At this rate the enlargement at the terminal of the-Gorge would take place, Dr. Wright estimates, in somewhat less than ten thousand years. No accounts have been kept by the railroad of the amount of fallen material, but some estimate can be made from the cost of removal of the falling stone, together with the observations of the watchmen, one of whom has been in the employ of the railroad in this capacity for twelve years, and also by noticing the distance to which the cliff has receded since the construction of the road.
Only a superficial observer can see at once that the amount of removal has been greatly in excess of the rate mentioned above. The watchman, of whom mention has been made, was in the employ of the cornpany which constructed the road in 1854, and therefore knows where the original face of the cliff was located. At one point, where the road descends to the Clinton limestone, the whole face of the Niagara shale is laid bare. Here the shale has been removed to a distance of twenty feet from its original position, and the rocks forming the roof overhang to about that distance. Now this mass of shale must have been removed since 1854. This would require a rate of disintegration much in excess of the one assumed. Necessarily some allowance must be made for the fact that the atmospheric agencies have here had a fresh section of the shale upon which to work. Yet making all due allowance for the above condition, the rate at the mouth of the Gorge could not have been much less than that assumed above. The actual process of the enlargement has been periodic. As the falling shale undermines more and more the capping hard layers, from time to time these latter fall in immense masses. Any calculation of age based upon a few years of disintegration would be worthless; but one based upon centuries would come very near a true average. The walls of the Gorge were at first perpendicular, but as the undermining process goes on they become sloped more and more, the falling masses forming a protection to the lower parts of the softer strata. One fact, however, to be noticed is that this protecting talus has never as yet reached so high as to stop the work of the disintegrating agencies. The horizontal distance from the water’s edge back to the face of the Niagara limestone, which forms the top of the cliff, is 38o feet. On the above assumption of the rate of recession as one-fourth of an inch annually, the rate at the top of the cliff must have been about one-half inch for each year. From the observations made, it is difficult to believe that the retreat of this upper portion has been at a lower rate than a half-inch yearly; if this be true, this new line of evidence places the birth of the Niagara and the beginning of the cutting of the Gorge at Lewiston at about ten thousand years ago.
The history of the Great Lakes and the birth of Niagara have a different interest for us, than alone to form the connecting link between the present and a past age devoid of life. Closely connected with this geologic history is the history of the human race. Unfortunately for us, the men inhabiting these parts in prehistoric ages have not left the traces of their existence upon the rocks and sands as have the waters of Niagara and the Lakes. Meagre, however, as is our knowledge we are still confident that man has been a comrade of the river during its entire history. Much to our disappointment, he was not possessed with the means of recording his knowledge for the satisfaction of future generations. Probably no such thought ever entered his brain. All that we know is, that along the old deserted shores of Lake Ontario in New York, which now form the Ridge Road, he constructed a rude hearth and built a fire thereon. The shifting of elevation or the rising of the surface of the lake buried beneath the waters hearth, ashes, and charred sticks, and thus by a mere accident do we know that human history extends back at least as far as the Ice Age.
In these modern days, when we are prone to believe that all forms of animate existence and inanimate as well have been the result of an evolution, we cannot think of the man who possessed the art of fire as the primeval man. Whatever age may be assigned to the Niagara, whatever may be the antiquity of that great cataract, upon which we are wont to look as everlasting, the age of the human race must be considered greater.
The Niagara River:Niagara River – Buffalo And The Upper NiagaraNiagara River – From The Falls To Lake OntarioNiagara River – The Birth Of NiagaraNiagara River – Niagara Bond And FreeNiagara River – Harnessing Niagara FallsNiagara River – A Century Of Niagara CranksNiagara River – The Old Niagara FrontierNiagara River – From La Salle To De NonvilleNiagara River – Niagara Under Three FlagsNiagara River – The Hero Of Upper Canada