been imbedded there; and in our explorations of the shore, we always carefully scrutinized such specimens, both with the view of observing whether they retained the superficial markings of Sigillariæ, and with reference to the fossils contained in them. It was while examining a pile of these "fossil grindstones" that we were surprised by finding on one of them what seemed to be fragments of bone. On careful search other bones appeared, and they had the aspect, not of remains of fishes, of which many species are found fossil in these coal measures, but rather of limb bones of a quadruped. The fallen pieces of the tree were carefully broken up, and other bones disengaged, and at length a jaw with teeth made its appearance. We felt quite confident, from the first, that these bones were reptilian; and the whole, being carefully packed and labelled, were taken by Sir Charles to the United States, and submitted to Prof. J. Wyman of Cambridge; who recognised their reptilian character, and prepared descriptive notes of the principal bones, which appeared to have belonged to two species. He also observed among the fragments an object of different character, apparently a shell; which was recognised by Dr. Gould of Boston, and afterward by M. Deshayes, as probably a land-snail, and has since been named _Pupa vetusta_. The specimens were subsequently taken to London and reexamined by Prof. Owen, who confirmed Wyman's inferences, added other characters to the description, and named the larger and better preserved species _Dendrerpeton Acadianum_, in allusion to its discovery in the interior of a tree, and to its native country of Acadia or Nova Scotia. It is necessary to state in explanation of the fragmentary character of the remains obtained, that in the decay of the animals imbedded in the erect trees at the Joggins, their skeletons have become disarticulated, and the portions scattered, either by falling into the interstices of the vegetable fragments in the bottom of the hollow trunks, or by the water with which these may have sometimes been partly filled. We thus usually obtain only separate bones; and though all of these are no doubt present in each case, it is often impossible in breaking up the hard matrix to recover more than a portion of them. The original description by Owen was therefore based on somewhat imperfect material, but additional specimens subsequently found have supplemented it in such a manner as to enable us somewhat completely to restore in imagination the form of the animal, which, though much smaller than _Baphetes_, agrees with it in its sculptured bones, in its bony armature, especially beneath, and in its plicated teeth. [Illustration: Humerus and Mandibles of Dendrerpeton Acadianum. Natural size, with one of the teeth enlarged. (From a Photograph.) The specimen illustrates the sculptured bones of Dendrerpeton and its plaited teeth, as well as large size and massive development of the arm bone.]