There is no turning over a leaf in the many-paged book of geologic investigation, without finding the frequent application of thoughts like these. Every part of the crust of the earth has its uses, and uses, too, that are peculiar to _it_; and as we have endeavoured hitherto to point out the economic uses of each formation in the great onward progress of humanity, we shall not find ourselves at a loss in this respect, now that we enter the second division of the secondary rocks. We commence with the Lias.[78] During the new red sandstone period, clay and marl were being deposited at the bottom of the seas and lakes then in existence. These were the natural degradations of existing rocks; into these soft deposits sunk various pre-Adamite remains, finding in the soft argillaceous beds ready to receive them the “possession of a burying-place” provided for them by the infinite Creator. Here they remained until in process of time, at the close of the new red sandstone period, these beds and their contents were upheaved from beneath the ocean, apparently without much violence; and becoming hardened by the chemical action of sun and wind, present us with the formation we are now studying, rich in its peculiarly characteristic fossils. The name lias, or layers, indicates the finely stratified condition of the rocks, and affords proof of the tranquil method of their deposit and upheaval. They stretch in a north-easterly direction from Lyme Regis, in Dorsetshire, where it may be seen on the open coast cliffs for about four miles, on to Whitby, in Yorkshire, where also it lies open to the sea, in cliffs of considerable elevation, and lying conformably with other strata, and is thus particularly favourable to geologistic examination. It is in the shales of the lias at Whitby, and at Lyme Regis, that most of the extraordinary and remarkable fossils have been met with that we are about to describe, and for which this formation is so justly renowned. Indeed, so far as palæontology, or the knowledge of ancient beings, is concerned, there is no formation more full of interest to the student. Here we meet for the first time with the ammonite. We will introduce him first in his fictitious, and then in his real character, and this we do to show how science dispels the follies of ignorance and superstition. The ammonites were once supposed to be petrified snakes—indeed they are even now called by the ignorant, “_snake-stones_;” and the pleasant little legend about these snake-stones was this, that St. Hilda, who once resided near Whitby, was very much annoyed, as any matron would be, especially if she kept an establishment for young ladies, as St. Hilda is alleged to have done, by the multitude of snakes that infested the place, and disturbed her equanimity. Accordingly, she set to work, and having first prayed their heads off, then prayed the snakes into stone. In Scott’s “Marmion” the legend reads thus:—