GEOLOGICAL PAPERS. 95 



were present in several specimens. I suppose this unique amphibian 

 was an ancient frog. The skull is very much compressed vertically ; 

 the mandibles are usually locked together with the maxillae ; at the 

 chin the jaws are only about half an inch thick, while the horns are 

 an inch and a half. I found several skulls that measured over a foot 

 from the end of the premaxilla to the distal point of the horns. The 

 whole skull appears as a comical imitation of the man in the moon 

 when he is half full. The very beautiful sculpture on all the outer 

 bones of the skull is remarkable. The vertebras have twin spines on 

 each side of the centra. I think, when alive, this frog must have been 

 six feet long. In another species I discovered, of the same genus, the 

 skull was much narrower behind. It was beautifully cleaned by long 

 erosion, and so perfectly preserved that it was not difficult to believe 

 it was a recent specimen. 



As a rule, all the fossils of this region are covered with a thin sili- 

 ceous matrix that is difficult to remove ; when exposed to the weather 

 for a long time this is sometimes worn off. This region was the home 

 of Cope's great salamander, Eryops megacephalus, which ought to 

 mean flat-headed. When we compare our living American salaman- 

 ders, that rarely exceed eight inches, with this grandfather of all the 

 mud puppies, we are struck with the enormous proportions reached 

 by Eryops during the Permian. I found an absolutely perfect skull 

 this year that was about twenty inches long, including the bones that 

 support the tongue. It is covered with a thin, red, siliceous matrix, 

 which I hope can be removed. All the outer bones of the skull are 

 beautifully sculptured. The bones that support the broad, flat quad- 

 rate are projected well back of the base of the skull. The lower jaws 

 extend still further back and are more loowerful than those of an ox. 

 A single row of large and small teeth, conical in shape, occupy the 

 jaws, while the palatines carry six sets of two powerful teeth each, 

 placed closely together, three sets on each side of the roof of the 

 mouth. The skull is vertically compressed, but, unlike Dlplocaulus, 

 the eyes are placed well back in the face. The occipital condyles are 

 shallow, saucer-like pits. The creature was about ten feet long. 



I found a nearly complete skeleton of this huge animal for Profes- 

 sor Cope in 1896, under peculiar circumstances. It lay at right angles 

 to a large cattle trail over which thousands of Texas cattle had made 

 their weary pilgrimage to Kansas and the North, and the constant 

 wear of countless feet had worn off the flint-like matrix and exposed the 

 completely petrified bones, while on the ridges they were not exposed 

 at all, except in cross-section caused by breaks in the rock. The ver- 

 tebrae are of lowly type. The centrum is composed of three distinct 

 bones, the central or plurocentrum, and the two lateral ones or hypo- 



