Ca. XXV.J 



AIR-BREATHING REPTILES. 

 Fie. 513. 



399 



Series of reptilian footprints in the coal-strata of "Westmoreland 

 county, Pennsylvania. 



a. Mark of nail ? 



gions ; whereas, when it afterwards dried up and shrank, it would be too 

 hard to receive such indentations. 



No less than twenty-three footsteps were observed by Dr. King in the 

 same quarry before it was abandoned, the greater part of them so ar- 

 ranged (see fig. 513) on the surface of one stratum as to imply that 

 they were made successively by the same animal. Everywhere there 

 was a double row of tracks, and in each row they occur in pairs, each 

 pair consisting of a hind and fore foot, and each being nearly equal 



