234 SCULPTURED FOOT-PRINTS. [CHAP. XXXVII. 



field, having the main bed of coal, called the Pittsburg seam, three 

 yards thick, a hundred feet above it, worked in the neighborhood, 

 and several other seams of coal at lower levels. The impressions 

 of Lepidodendron, Sigillaria, Stigmaria, and other characteristic 

 carboniferous plants, are found both above and below the level of 

 the reptilian loot-steps. 



We may safely assume that the huge reptile which left these 

 prints on the ancient sands of the coal-measures was an air- 

 breather, for its weight would not have been sufficient under 

 water to have made impressions so deep and distinct. The 

 same conclusion is also borne out by the casts of the cracks above 

 described, for they show that the clay had been exposed to the 

 air and suri, so as to have dried and shrunk. As we so often see 

 the ripple mark preserved in sandstones of all ages, and in none 

 more frequently than in the American and European coal strata, 

 we ought not to feel surprised that superficial markings, such as 

 foot-prints, which are by no means more perishable or evanescent 

 in their nature, should have been faithfully preserved down to 

 our times, when once the materials had been hardened into stone. 



There are some bare ledges of rock, composed of pure white 

 quartzose grit of the coal-measures, standing out exposed above 

 the general level of the ground, in many places near Greensburg, 

 especially near Derry, in Westmoreland County, about fourteen 

 miles north of G-reensburg. They are so bare that scarcely any 

 lichens grow upon them, and on some of them the foot-prints oi 

 birds, as well as those of dogs and some other quadrupeds have 

 been artificially cut. After examining them carefully, I entertain 

 no doubt that they were sculptured by Indians, for there are many 

 Indian graves near Deny, arid one of their paths, leading through 

 the forest from the Alleghany Mountains to the west, lay precisely 

 in the line of these curious carvings. The toe joints in the feet 

 of the birds thus cut are well indicated, as might have been ex 

 pected, for the aboriginal hunting tribes of North America were 

 skillful in following the trail of all kinds of game, and are known 

 to have carved in some places on rocks, many rude imitations of 

 the external forms of animals. If, therefore, they were sometimes 

 tempted to use the representation of foot-prints as symbols of the 



