Although we have necessarily treated the subject of fossil footmarks in a very brief way, sufficient has been said to show that this new branch of Paleontology may lead to interesting results. The fact that they are, in some manner, peculiar to this region, seems to call upon our Society to obtain a sufficient number of specimens to exhibit to scientific men a fair representation of the condition of Ichnology in this quarter of our country; and we have therefore great reason to congratulate ourselves, that, through the vigilance and spirit of our members, the Society has the expectation of obtaining a rich collection of ichnological specimens.
FOSSIL IMPRESSIONS.—II.
Since writing the preceding article, I have been able to obtain, through the kindness of President Hitchcock, a number of additional specimens of fossil impressions. By the aid of these, I may hope to give an idea of the system of impressions, so far as it has been discovered, without, however, attempting to enter into minute details. For these, I would refer to the account of the "Geology of Massachusetts," by President Hitchcock; to his valuable article published in the "Memoirs of the American Academy;" and to his geological works generally.
The numerous tracks which have been assembled together in the neighborhood of Connecticut River have afforded an opportunity of prosecuting these studies to an extent unusual in the primitive rocky soil of New England. These appearances are not, indeed, wholly new. Such traces had been previously met with in other countries; but, in their number and variety, the valley of the Connecticut abounds above all places hitherto investigated.
Twenty years have elapsed since the study of Ichnology has been prosecuted in this country; and, in this period of time, about forty-nine species of animal tracks have been distinguished in the locality mentioned, according to President Hitchcock; which have been regularly arranged by him in groups, genera, and species.
I propose now to lay the specimens, recently obtained, before the Society, as a slight preparation for the more numerous and more valuable articles which they are soon to receive.
The traces found on ancient rocks, as has been shown in the previous article, are those of animals, vegetables, and unorganized substances. The traces of animals are produced by quadrupeds, birds, lizards, turtles, frogs, mollusca, worms, crustacea, and zoophytes. These impressions are of various forms: some of them simple excavations; some lines, either straight or curved, and others complicated into various figures.
President Hitchcock has based his distinctions of fossil animal impressions on the following characters, viz.:—