The separation of the dry land from the waters was, doubtless, effected through the instrumentality of means. The igneous theory of granite, and other amorphous rocks, is in accordance with this supposition, which thereby imparts a sacred and peculiar interest to all our investigations respecting the origin and elevation of mountains. The range of geological investigation is thus wide as the circumference of the globe—deep as the foundations of the earth—and sublime thoughts are everywhere awakened of Him—
Whose dwelling is the light of setting suns,
And the round ocean, and the living air,
And the blue sky, and in the mind of man:
A motion and a spirit that impels
All thinking things, all objects of all thought,
And rolls through all things!
CHAPTER III.
THE SILURIAN SYSTEM. FIRST TRACES OF LIFE.
The group of rocks on which we next enter are termed fossiliferous, that is, there is contained in their hard stony substance the impressions and actual remains of organic bodies. As we proceed upward through the series in their ascending order, we will find different rocks distinguished by different classes of fossils, and characterized by distinct lithological appearances. They are in consequence divided into different formations, and called by particular names. Hence the origin of systems, of which there are five or six recognized by geologists, separable into their respective groups of strata. Descending from the primary, the highest as well as lowest in the series of rocky combinations, the group which first invites attention is the Silurian; so denominated because the strata are widely spread over the districts in England and Wales, anciently inhabited by a people called the “Silures.” They are found in various quarters of the world, and occupy a large area on the southern frontiers of Scotland.