28 



Forty-second Annual Report on the 



Esq., F. G. S., Director of the Geological survey of Canada, in the 

 Quarterly Journal of the Geological Societ}^, volume VII, 1852, 

 page 247.* At page 250f of the same volume, Prof. Owen gives 

 a detailed description of them. 



At the time of the publication of this article, Prof. Owen 

 regarded those impressions as probably due to some Chelonian 

 Reptile, and that " the choice of reference lay between the Batrachia 

 and Ghelonia" 



In the Quarterly Journal of the Geological Society, volume VIII, 

 18534 there is a very interesting article on the Potsdam sand- 

 stone, and its Geological and Palseontological relations, under the 

 following title : " On the Foot-prints occurring in the Potsdam 

 sandstone of Canada. By W. E. Logan, Esq., E. G. S." 



This article is very fully illustrated (1) by a colored geological 

 map (plate VI) of a part of Canada "to illustrate Mr. W. E. 

 Logan's paper on the Foot Tracks in the Potsdam Sandstone." 

 (2) Plate VII. A plan of the Field with rock surfaces bearing 

 Ripple-marks and Foot-tracks. 



(3) Plate VIII. Enlarged portions of Rock-surfaces of the 

 Field-plan shown on plate VI. 



Following this paper is the one by Professor Owen§ fully 

 describing and illustrating these tracks and foot-prints from the 

 Potsdam sandstone of Canada. In this paper there are described 

 six species of Protichnites, viz.: 1. Protichnites septem-notatus ; 2. 

 P. octonotatus ; 3. P. latus ; 4 P. multinotatus ; 5. P. lineatus ; 6. 

 P. alter nans. 



In this paper Professor Owen, after making a careful study of 

 all the known forms of tracks in the geological formation, arrives 

 at the " conviction that they were not made by any Chelonian 

 Reptile nor by any vertebrated animal." 



The impressions give evidence that the animal making them 

 was furnished with more than two pairs of limbs, and they 

 were referred to some large form of Crustacean, probably 

 allied to the existing Limulus. At a latter date Prof. J. W. Dawson 



* "On the occurrence of a track and foot-prints of an Animal in the Potsdam sand- 

 stone of Lower Canada, by W. E. Logan, Esq., F. G. S." 



t " Description of the impressions on the Potsdam sandstone discovered by Mr. 

 Logan in Lower Canada, By Prof. Owen, F. E. S." 



+ "Quart. Journal of the Geol. Soc, vol. VIII, p. 199." 



§ Description of the Impression and Foot-tracks of the Protichnites from the Pots- 

 dam sandstone of Canada. By Professor Owen, F. R. S., F. G. S. 



