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But the drift is only a superficial and recent addition to the soil, resting loosely above the other geological deposits, and arising, as we shall see, from very different causes. In this article I have intended to limit myself to a general sketch of the formation of the Laurentian Hills with the Azoic stratified beds resting against them.
By a most careful analysis of the structure of the rocks in these ancient patches of land, tracing all the dislocations of strata, all the indications of any disturbance of the earth-crust whatsoever, Élie de Beaumont has detected and classified four systems of upheavals, previous to the Silurian epoch, to which he refers these islands in the Azoic sea.
I am aware that part of the theory here propounded as to the probable mode of formation of the immense sedimentary beds of the Archaic or Azoic period is not altogether orthodox i.e., that the origin of these beds is largely due to the ejection of mud, sand, and ashes from subterraneous sources, which, settling in shallow seas, were afterwards altered to their present form.
But its titanic tablelands consist of those azoic rocks which form the very roots of all the other mountains in the world, and which are so old, so immeasurably older than any others now standing on the surface of the globe, that their Laurentians alone have the real right to bear the title of "The Everlasting Hills". Being azoic these Laurentians are older than the first age when our remotest ancestors appeared in the earliest of animal forms, millions and millions of years ago.
Although, from the condition in which we find it, this first granite range has evidently never been disturbed by any violent convulsion since its first upheaval, yet there has been a gradual rising of that part of the continent; for the Azoic beds do not lie horizontally along the base of the Laurentian Hills in the position in which they must originally have been deposited, but are lifted and rest against their slopes.
Limestone and Shale of Carrara. Metamorphic Strata of older date than the Silurian and Cambrian Rocks. Order of Succession in metamorphic Rocks. Uniformity of mineral Character. Supposed Azoic Period. Connection between the Absence of Organic Remains and the Scarcity of calcareous Matter in metamorphic Rocks.
Had they determined to study the subject of life, as we have done, from the Bible as well as from nature, they would have commenced at these toad-producing rocks, and worked their way upward to the source of all life, and not downward to the vanishing point that where animal life ceases in the azoic rocks.
But the drift is only a superficial and recent addition to the soil, resting loosely above the other geological deposits, and arising, as we shall see, from very different causes. In this article I have intended to limit myself to a general sketch of the formation of the Laurentian Hills with the Azoic stratified beds resting against them.
The oldest sedimentary rocks are devoid of fossil remains and so they are called the Azoic or Archæan. They comprise about 30,000 feet of strata which seem to have required at least 20,000,000 years for their formation.
The Laurentian Hills form, then, a granite range, stretching from Eastern Canada to the Upper Mississippi, and immediately along its base are gathered the Azoic deposits, the first stratified beds, in which the absence of life need not surprise us, since they were formed beneath a heated ocean.
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