An eminent Geologist, named Dr. Mantell, has very beautifully and poetically termed rocks “The Medals of Creation.” As on coins and medals we see stamped enduring records of great historical events, so upon the rocks are written by the finger of God, a history of some of the mighty changes which the earth has undergone, and fossil shells are among the plainest and most easily read of the characters or letters, in which these truths are written. As Dr. Harvey, in his “Sea-side Book,” observes, “Shelly-coated mollusca have existed in the waters of the sea and in rivers, from a very early period of the world’s history, and have left in its most stratified rocks and gravels abundance of their shells preserved in a more perfect manner than the remains of most other animals. Now as the species in the early rocks differ from those found in later formations, quite as much as the latter from the mollusca of our modern seas, the gradual change in the character of the embedded shells marks a certain interval of time in the world’s history.” So we see that these rocks are the leaves of a great book, written all over with wonderful truths, and those who study such sciences as Geology and Conchology, are enabled to read much that is there written. Every fossil shell that such a student picks out of the chalk, or limestone, is like a letter in the Alphabet of Creation; it has a significance, or meaning, and a number of such put together, form as it were, words and sentences, that can be made up into chapters, full of instruction, aye, and of amusement too. The study may seem a little dry at first, but never mind, go on, and you will soon be rewarded for your diligence, by the wonders that will unfold themselves to your understanding—the fresh and delightful views which you will obtain into the wide universe, the new and enlarged ideas of the wisdom and goodness of the Creator, and of the formation, habits, and connexion each with each of his various creatures. Properly to treat of fossil shells, would require a book of itself, and a large book too; we can here but allude to the subject, as a part, and a very important and interesting part of the study of Conchology; more will be said about it in a volume which we purpose writing for this series, on Rocks, and the petrified organic remains found in and about them. “Those relics of an older world, which tell Of changes slow or sudden, that have past Over the face of nature; fossil shell, Shark’s tooth, and bone of megatheran vast, Turned into stone, and so preserved to show Man of those things whereof he ought to know.” BEAUTIFUL SHELLS. UNIVALVES.