On ascending the canyon the glaciation is very conspicuous, and becomes more and more beautiful at every step.
The glaciation is distinct also up the sides of the canyon 1000 feet above its floor.
Over the lip of this cliff, and in the bed of the canyon above, and up the sides of the cliff-like walls, 1000 feet or more, the most perfectglaciation is found.
There are many evidences that the main period of glaciation west of the Rocky Mountains was considerably later than that in the eastern part of the continent.
We are not aware that any incontestable evidence has been presented in America of any glaciation previous to that of the Glacial period.
The interpretation is clear: In the early stages of glaciation the Welsh ice spread without hindrance to, and laid down, bed No.
The glaciation was not limited to masses which were firmly caught between the ice and the solid ledges, and it was in every case essentially a slipping and not a rolling movement.
From the very necessity of the case, glacial erosion diminishes as the limit of the extent of the glaciation is approached.
It is a question among geologists whether or not the glaciation west of the Rocky Mountains was contemporaneous with that of the eastern part of the continent.
At any rate, the intenseglaciation of the Pacific coast seems to have been considerably later than that of the Atlantic region.
Period of most severe submergence of the great plains, glaciation and maximum development with possible contemporaneous of the great Cordilleran Glacier.
With the spread of glaciation the main crystalline areas whose alteration is the chief source of depletion become covered and frozen, and the abstraction of carbon dioxide by rock alteration is checked.
Chamberlin takes up a suggestion of Tyndall's that the periods of terrestrial glaciation might be dependent upon the carbon dioxide of the atmosphere, the peculiar competence of which to retain solar heat he had demonstrated.
During certain periods of this time of intense glaciation great additions of ice-borne debris must have been made to the continental shelf.
The detached areas of glaciation in the western portion of the United States are here assigned to the Wisconsin stage, but in the Rocky Mountains and Sierra Nevada there are records of two ice advances.
The great depressions, together with the intervening highland, are therefore believed to be responsible for the absence of glaciation in the driftless area.
The effect ofglaciation on topography has been sketched, but the topography in turn exerted an important influence on the direction of ice movement.
The streams outside the area ofglaciation were less seriously disturbed.
Thus in North America, where the glaciation was more intense, and the ice-cap extended some ten degrees further south than in Europe, it might well be that it was later in retreating and disappearing.
However, this first period of elevation and of intense glaciation passed away, and was succeeded by one of depression and of milder climate.
If high land in high latitudes is the principal cause of the present glaciation of Greenland, still higher land must have been so in causing the still greater glaciation of the former period.
This turns very much on whether the first great glaciation was Pliocene or Quaternary, and must be decided partly by the order of superposition and partly by the fauna.
But the geological evidence is much more conclusive for the greater elevation of the land during the periods of greater glaciation as well as for its depression during the inter-glacial period.
If the Elephas Meridionalis is a Pliocene and not a Quaternary species, we must admit, with the great majority of continental geologists, that the first and greatest glaciation fell within the Pliocene period.
We cannot draw a line at the culmination of the last great glaciation and say, here the glacial period ends and the post-glacial begins.
This is because more lakes of the present time have come into existence as direct or indirect results of glaciation than by any other cause.
Another objection to the hypothesis as an explanation of Ice Ages is that it is directly opposed by the fact of widespread glaciation at low latitudes either side of the equator during the late Paleozoic Ice Age.
These evidences of glaciation directly refute the old idea, based upon the nebular hypothesis, that the climate of the Paleozoic was distinctly warmer than now.
There is a total absence of records of glaciation within this area, and so we here have an excellent sample of the kind of topography which prevailed over the northern Mississippi Valley just before the advent of the ice.
By variations in the consumption of carbon dioxide, especially in its absorption and escape from the ocean, the hypothesis attempts to explain the periodicity of glaciation (i.
But it is unnecessary for our purpose to pursue this question further, for with the arrival of modern man, after the last glaciation was past, Neanderthal man disappeared.
I must now pass rapidly in review the facts relating to the glaciation of the mountainous regions which lay outside of the area covered by the northern ice-sheet.
The phenomena which I have thus briefly sketched suffice to show that the epoch of local glaciation is to be clearly distinguished from that of the latest general mer de glace.
It was not until all those valleys had come to assume much the appearance they now present that general glaciation supervened.
The direction of the glaciation in the north of Skye, which is towards north-west, shows that the glacier-mass which overflowed that area must eventually have reached the shores of the Long Island.
Many speculations have been indulged in as to the cause of this curious connection between glaciationand depression; these, however, I will not consider here.
For the limits of the greater glaciation on the Continent, Habenicht, Penck, Nikitin, and Nathorst have been followed.
Of the glaciation of our own land I need say very little.
The facts which I have now briefly indicated suffice to show that during the climax of glaciation North America must have presented very much the same appearance as Europe.
More recently other views have been advanced to explain the apparently causal connection between glaciation and submergence, but these need not be considered here.
One cannot deny, indeed, thatglaciation might be induced locally by elevation of the land.
Those who advocate the "earth-movement hypothesis" as an explanation of the origin of extensive glaciation have welcomed Mr. Jamieson's view as harmonising well with their conclusions.
In the Rockies, the Cascades, and the Sierra Nevadas glaciation was common as far south as Colorado and southern California, respectively, and snowfields were doubtless extensive enough to make these ranges ribbons of white.
Its effect, however, was always to cause glaciationexactly where it would be expected and not in unexpected places as actually occurred.
On the other hand, Kirk's recent discovery of glacial till in Alaska between beds carrying an undoubted Middle Silurian fauna indicates glaciation at a time when there was little movement of the crust so far as yet appears.
In the southern hemisphere glaciation at low latitudes was less striking than in the northern hemisphere.
Nevertheless, fairly extensive glaciation existed much nearer the equator than is now the case.
The testimony of ancient glaciation as to the slight difference in the climate and therefore in the atmosphere of early and late geological times is almost as clear as that of life.
Or there might be glaciation in high latitudes, such as that of southern Alaska in the Middle Silurian, and none elsewhere.
Their distribution shows that at the time of maximum glaciation the strong winds along the south coast of Ireland were from the northeast while today they are from the southwest.
This would tend to produce low temperature and thus make the conditions favorable for glaciation as soon as an accentuation of solar activity caused unusual storminess.
It is that of a cold climate, accompanied by glaciationand boulder deposits.
After having established the criteria by which the work of moving ice is to be recognized in regions of active glaciation, the task of identifying the results of earlier glaciation elsewhere has been carried on with unabated energy.
Chamberlin based a theory of glaciation on the depletion of the carbon dioxide of the air ("An Attempt to frame a Working Hypothesis of the cause of Glacial Periods on an Atmospheric Basis," Jl.
In Asia the evidences of a former extension of glaciation are traceable in the Himalayas, and northward in the high ranges of China and Eastern Siberia.
The maximum glaciation of the Glacial period was clearly centred around the North Atlantic.
The localization of glaciation is assignable to the two great areas of permanent atmospheric depression that have their present centres near Greenland and the Aleutian Islands respectively.
Glacial epoch, Saxonian, deposits of the period of maximum glaciation when the northern ice-sheet reached the low ground of Saxony, and the Alpine glaciers formed the outermost moraines.
In a similar manner Professor Chamberlin and other American geologists have recognized the following stages in the glaciation of North America: The Champlain, marine substage.
The glaciation of the Scotch mountains was traced by him to the height of at least 3000 feet.
Even in that case, however, it is difficult not to suppose that the Glen Roy country participated in the downward movement which sank part of Lanarkshire 525 feet beneath the sea, subsequently to the first great glaciation of Scotland.
But that the larger part of the glaciation of that country has been supramarine, I am willing to concede.
On the whole, I conclude that the Glen Roy terrace-lines and those of some neighbouring valleys, were formed on the borders of glacier-lakes, in times long subsequent to the principal glaciation of Scotland.
This last stage of glaciation may have coincided with that of the parallel roads of Glen Roy, spoken of in the last chapter.
In Ireland we encounter the same difficulty as in Scotland in determining how much of the glaciation of the higher mountains should be referred to land glaciers, and how much to floating ice, during submergence.
In like manner the glaciation although identical in kind is on so small a scale in the existing Alpine glaciers as at first sight to disappoint a Swedish, Scotch, Welsh, or North American geologist.
To him the two or three labored guesses that Sir Charles suggested or borrowed to explain glaciation were proof of nothing, and were quite unsolid as support for so immense a superstructure as geological uniformity.
As before remarked, all the regions which have been subjected to glaciation are still each year brought temporarily into the glacial state.
Thus the snowfall of northern Europe, which serves to maintain the glaciation of that region, and, curiously enough, in some measure its general warmth, depends upon the movement of the Gulf Stream from the tropics to high latitudes.
Thus the most evident cause ofglaciation must be sought in those alterations of the land which affect the movement of the oceanic currents.
More information is available about the Wisconsinan, or last, glacial age, than about the earlier ones, because the last glaciation in many montane areas destroyed evidence of earlier glaciations.
Wisconsinan glaciation again rendered Canada uninhabitable, and it is quite possible that extensive areas in the Rocky Mountains, the Cascades and the Sierra Nevada were heavily glaciated.
A Characteristic feature of the valleys of the Peruvian Andes below the zone of glaciation but within the limits of its aggraditional effects.
But evidences of more extensive mountain glaciation in the past do not in themselves prove a change in climate over the whole earth.
The absence of bergschrunds is also noteworthy in many localities where formerly glaciationtook place.
There would be evidences of glaciation all about the ruins of the former loftier mountain, but there would be no living glaciers.
Glaciers formed upon it in the Ice Age and glaciation intensified the contrast between it and the left-hand section; not so much by intensifying the relief as by diversifying the topographic forms.
The down-cutting of the stream in the canyon cycle was generally checked by glaciation and was superseded by aggradation.
Where glaciation at the higher levels and vigorous erosion along the canyons have taken place, the former soil cover has been removed; elsewhere it is an important feature.
Before glaciation on a larger scale had set in the right-hand section of the diagram had a greater relief.
In some, glaciation was carried to the point where only skeleton divides remained, in most places broad massive ridges or mountain knots persist.
Moreover, Reiss[46] denies that the hypothesis of universal climatic change is supported by the facts of a limited glaciation in the High Andes of Ecuador; and J.
In the succeeding layers of this grotto the changing forms of animal life demonstrate the effect of the fourth glaciation and the cooling of the climate toward the close of Mousterian times.
The fourth glaciation passed by, and the Upper Palaeolithic flint workers again returned and left the debris of their industry in the layers of loam which swept down the slopes of the valley from the surrounding hills.
At the commencement of the fourth glaciation large glaciers descended over the Scottish mountain valleys and filled many of them even to the sea; the coast subsided at least 130 feet in this region.
The second glaciation was by far the greatest both in Europe and America.
In the Alps the third glaciation sent vast ice-floes along the valley of the Rhine, into eastern France, and into the valley of the Po, where this glaciation was even more extensive than the second.
Fourth or lowest terrace of the Fourth Glaciation on the fourth erosion level.
My speculation was based upon the former glaciation of the northern temperate zone, and the inference of a warmer period preceding and perhaps following.
Former Glaciationas explaining the Present Dispersion of Species.
On this continent one species, at least, had reached to the vicinity of its present habitat before the glaciation of the region.
He placed the stratigraphic position of the fauna as definitely Upper Pleistocene, probably deposited in both Illinoian glaciation and during the Sangamon interglacial.
The Hay Springs local fauna is considered to have been deposited in late Kansan glaciationor in early Yarmouth interglacial by Shultz and Tanner (op.
The Irvingtonian provincial age is currently regarded as Middle Pleistocene and includes the late Kansan glaciation (that part occurring after the glacial maximum) and the Yarmouthian interglacial (see Hibbard et al.
These warm winds probably counteracted the cooling effect of glaciation in the lowlands and thereby maintained tropical conditions near the seas.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "glaciation" in a variety of sentences. We hope that you will now be able to make sentences using this word. Other words: berg; calf; chilling; floe; freezing; glacier; glaze; ice; iceberg; icicle; sleet; slob; sludge
