ARTICLE XXI. 



On the Fossil Fooi-Marks in the Red Sandstones of Pottsvillc, Schuylkill County, Penna. 



By Isaac Lea. Rcud April 2d, 1S52. 



When I communicated to this society, in 1849, the discovery of "foot-marks" of a 

 Saurian animal in the "red shale" formation, No. 11, of Prof. H. D. Rogers, near Mount 

 Carbon, south of Pottsville, I mentioned that in characterizing and naming this new 

 animal (Sauropus jjrimctvus,) I would at a future time offer to the society a more length- 

 ened and accurate description, with correct figures of this remarkable and interesting 

 specimen. A subsequent visit to the locality has not induced me to change my views as 

 to its position in the series of the stratified masses of that district. 



After the discovery of this ancient Saurian had been made known, by my account of it 

 in the Proceedings of this society, Prof. H. D. Rogers stated, at the meeting of the 

 "American Association for the Advancement of Science," at New Haven, that these 

 "foot-prints in the red shale formation at Mount Carbon" were "of an age essentially 

 later than that attributed to them," — that " they occurred in a geological horizon only a 

 few hundred feet below the conglomerate which marks the beginning of the productive 

 coal series, in which series similar foot-prints, attributed to batrachian reptiles, have been 

 previously met with in Western Pennsylvania. Instead, therefore, of constituting a record 

 of antique reptilian life, earlier than any hitherto discovered, by at least a whole chapter 

 in the geological book, they carry back its age only by a single leaf." 



These and some farther observations were followed by remarks of Prof. Agassiz on the 

 character of these foot-prints, which he attributed rather to " the pectoral and ventral 

 fins of fishes of an ancient type, which probably had some power of locomotion out of 

 water."* 



At the meeting, in August, 1851, at Albany, Professor Rogers exhibited specimens 

 which he had procured from the same formation, (No. 11,) near to the same locality. 



* Proceedings of ihc American Association, 1850, p. 251. 



