312 ON THE FOSSIL FOOT-MARKS 



M. Verneuil considers that "if in two countries, a certain number of systems charac- 

 terized by the same fossils, are superimposed in the same order, whatever may be the 

 thickness or number of the physical groups of which they are composed, these systems 

 should be considered as parallel and synchronous." (Geol. Soc. Proc, vol. 4, p. 103.) 



I am aware that Prof. Rogers would arrange all the rocks, from the Potsdam sand- 

 stone inclusive, to the top of the coal rocks, in one " system," of about 30,000 feet in 

 thickness, characterized by peculiar organic remains, marking a long series of events, and 

 a vast lapse of time. lie said, in his address of 1844, "we behold one uninterrupted suc- 

 cession of deposits, closely linked by an unbroken sequence of animal and vegetable 

 remains;" that they "constitute a single system, the entire record of one immense con- 

 tinuous period, the collected gatherings of one prodigious sea." (Pages 19 and 20.) 



In these views I should not be disposed to go to the entire length. I am aware that in 

 Furope there is a great difference of opinion among the most able geologists. Sir 

 Charles Lyell now repudiates the theory of "successive development of organic life? and 

 advocates the wide field of " uniformation" which an able writer in a late Number of the 

 London Quarterly Review has most vigorously attacked and apparently settled. 



For the present it might be safest to view the divisions of the more ancient rocks as 

 forming two systems — the older and newer Palaeozoic rocks — and make the separation at 

 the Devonian (old red sandstone,) including it in the newer Palaeozoic rocks, which would 

 then embrace also the Carboniferous Limestone, the Conglomerate, the Coal measures, and 

 the Lower New Red Sandstone or Permian. The older Palaeozoic rocks would embrace all 

 the ancient sedimentary rocks below the Devonian. These are the views of Prof. Forbes 

 and other geologists, and they seem to me to be more nearly in accordance with the 

 present state of our knowledge of the strata and their organic contents. 



Having, I trust, vindicated myself in regard to the geological position in which I had 

 placed these remarkable " foot-prints," I shall proceed to regard some of their analogies, 

 and then give a more extended and accurate diagnosis of the imprints themselves, than I 

 did in my former communication, published in the Proceedings of this society, vol. 5, p. 91. 



When Cuvicr was engaged in fossil osteology, fossil foot-prints had not been observed; 

 but he remarked that the print of a foot clearly indicated the form of the teeth and the bones 

 which leave a mark. The first of these curious relics seems to have been observed in 

 Scotland, by Dr. Duncan, at Dumfriesshire, in the New Red Sandstone. These were made, 

 it is believed, by tortoises. Very shortly after this, the tracks of the Clicirothcririrn were 

 observed, in Saxony, in the same formation, and Dr. Dean and Professor Hitchcock, in 

 the New Red Sandstone, in the valley of the Connecticut river, observed various "foot- 

 marks," nearly all of which they attributed to birds, some being of gigantic size. In 1836 

 Prof. Hitchcock published an account of these Omithichniles, in the American Journal of 

 Science, and many valuable papers have been published since by him, by Dr. Dcane and 

 others. The two most important ones are those in the Transactions of the American 

 Academy, by Prof. Hitchcock, in vol. 3d, and by Dr. Deane, in vol. 4th. The Professor 

 considered that he had made out forty-nine species, twelve of which were quadrupeds; 

 four probably lizards; two Chelonians, and six Batrachians. The figures which he gives 



