1846.] LYELL ON FOOT-MARKS IN THE COAL-MEASURES. 419 



angle of 22°, so that the bird, after walking on the planes of strati- 

 fication, which are nearly horizontal, must have gone over the edges 

 also. Loose sand, capable of receiving an impression, could never 

 have acquired the present outline in a ledge of rock; and, on the 

 other hand, sand consolidated into stone, as this evidently was when 

 denuded, could never have been marked subsequently by any known 

 agency but the hand of man, in imitation of the feet of birds and 

 quadrupeds. 



In order to explain the great number of the foot-prints appearing 

 on so uneven a surface, and where several different stratified layers 

 of sandstone have been cut into, we should have to imagine that 

 there were originally a multitude of impressions on each super- 

 imposed layer, all nearly in one direction ; that wherever the denu- 

 ding action of water had happened to cut into any inferior layer, it 

 always laid open to view new tracks. But this hypothesis is so far 

 from being borne out by the facts, that after cutting into the stone 

 in more than twenty places, and removing small slabs with imprints 

 on them, Dr. King has never been able to detect a single indication 

 of a foot-mark in the rock below. 



One of the dog-like foot-prints on this Derry stone agrees with 

 one of those which are found in another locality, in Fayette county, 

 near Connelsville, nineteen miles from Greensburg, and about thirty 

 from Derry. Dr. King and the Rev. Mr. Hackey, who have visited 

 that place, inform me that unquestioned Indian hieroglyphics, and 

 the representation of a serpent and two human heads, are there to 

 be seen with bird tracks and those of hoofed quadrupeds. I have 

 seen good imitations of the foot-prints of birds brought to Indiana 

 by Dr. David Dale Owen from St. Louis, Missouri, on slabs of lime- 

 stone sculptured by Indians ; nor can anything be more probable, 

 than that the aboriginal inhabitants of North America, who are so 

 accustomed to trace and follow the trail of every kind of game, 

 should occasionally employ as symbols of birds and quadrupeds, an 

 imitation of the foot-prints which they leave on soft mud and sand. 

 As Dr. King agrees with me in abandoning as spurious all the im- 

 prints except those of the large reptile, I will not dwell longer on 

 the refutation of the evidence ; but I may mention that there are 

 numerous graves of Indians near the sculptured sandstone of Derry, 

 and it is known to have lain in the line of one of their principal 

 paths leading from the Alleghany mountains to the west. 



The rectification of a iew mistakes, with which some of the first 

 observations in this new field have been connected, is a matter of 

 small interest and moment compared to the important truth which 

 has been brought to light through Dr. King's exertions; — that the 

 land on which forests of Sigillaria and Lcpidodendron grew, gave 

 support also to large air-breathing quadrupeds. Few geologists will 

 now be prepared to believe that this single species or genus of rep- 

 tiles, or that one class only of vertebrated animals, had possession of 

 the islands and continents on which so widely-extended and mag- 

 nificent a vegetation flourished. 



It may be as well for me to add, that the rejection of the sup- 



