316 ANNUAL OF SCIENTIFIC DISCOVERY. 



ON THE REPTILIAN FOOT-PRINTS OF EASTERN PENNSYLVANIA. 



IN former numbers of the Annual of Scientific Discovery,* some 

 account has been given of reptilian foot-prints in the rocks adjacent to 

 the coal measures of Eastern Pennsylvania, discovered by Mr. Isaac C. 

 Lea, in 1849. As the exact position of these remains in the geological 

 series has been called in question, we copy, from the proceedings of the 

 Philadelphia Academy, the following remarks of Mr. Lea on this sub- 

 ject : 



" The geological position of this reptilian quadruped is of great 

 interest, from the fact that no such animal remains have heretofore 

 been discovered so low in the series. Those discovered by Dr. King, 

 in Westmoreland county, and described by Mr. Lyeil, in Silliman's 

 Journal, July, 1846, are in the western coal-field, only 800 feet below 

 the surface of the coal formation. (No. 13 of Prof. Rogers, the State 

 Geologist.) The position of the Pottsville 'foot-marks' is about 

 8500 feet below the upper part of the coal formation there, which is 

 6750 feet thick, according to Professor Rogers, and they are in the 

 1 red shale,'' (his No. 11,) the intermediate silecious conglomerate 

 (No. 12) being stated by him to be 1031 feet thick at Pottsville. 

 These measurements would bring these foot-marks about 700 feet below 

 the upper surface of the old red sandstone. A mass of coal-plants exists 

 immediately on the northern face of the heavy conglomerate, here tilted 

 ten degrees over the vertical, and forming the crest and ' back-bone ' 

 of Sharp Mountain. This conglomerate mass is about 150 feet thick 

 at the western side of the road, below Pottsville. On the same road 

 side, about 1735 feet from these coal-plants, is the face of the rock, 

 tilted slightly over the vertical, and facing the north. It is proper to 

 state, that the limestone of the old red sandstone exists here, about two 

 feet thick, and underlies these ' foot-marks ' sixty-five feet." 



The foot-marks in question are six in number, and very distinct. 

 They assimilate remarkably to those of the recent Alligator Mississippi- 

 ensis, and are somewhat analogous to the Cheirotheriwn. The name 

 proposed for them by Mr. Lea is Sauropus primozvus. 



NEW ENGLISH FOSSILS. 



MR. BOWERBANK, at the British Association, exhibited some few 

 specimens of the remains of a once gigantic bird, found in the London 

 clay, near Sheppy. He also exhibited drawings and restorations of 

 several species of Pterodactyles from the chalk formation, showing that 

 the great species of the chalk (P. Cuvieri) must have had a spread of 

 wing equal to 16 feet 6 inches ; whilst a second large species (P. com- 

 pressirosLris) was estimated at 15 feet. The largest species previously 

 well known, the P. macronyx of Buckland, from the lias, was only 

 computed at 7i inches from tip to tip of its expanded wings. 



At a meeting of the London Geological Society, Dec., Dr. Mantell 

 exhibited a fossil lizard, about six inches long, which had been sent him 

 to examine and describe by Mr. Duff, who discovered it near Elgin. 



* See Annual of Scientific Discovery, 1849, p. 231, et 1850, p. 314. 



