158 THE PERMO-CARBONIFEROUS RED BEDS OF 



The only forms listed as new are those indicated by bones which can not 

 be, by any possibility, referred to forms already known. Certain new humeri, 

 femora, scapulae, and so forth, are provisionally referred to Cricotus, Thero- 

 pleura, and others, as seems most probable. 



The most abundant genera in the bed are Edaphosaurus and Cricotus, 

 next comes a small form of Dimetrodon, with a good many bones of the larger 

 Dimetrodon incisivus, and some bones which appear to belong to Dimetrodon 

 gigas. The Cotylosauria are represented by a single imperfect vertebra of a 

 Diadectes of medium size and a single humerus of a large Diadectes, probably 

 D. maximus. This is very striking, as in the same region and at almost the 

 same horizon the bones of Diadectes are very common. Several jaws and some 

 limb bones and vertebrae of Bolosaurus occurred scattered through the bed. 



The probably aquatic Cricotus occurs in abundance, with fairly numerous 

 remains of Eryops, but it is singular that very few recognizable bones of the 

 smaller amphibians were found. Zatrachys and Trimerorhachis are among 

 the more common forms in the Wichita formation. The intercentra of these 

 forms are generally very abundant, but in the Brier Creek bed only a single 

 intercentrum and perhaps a humerus were found among the hundreds of 

 specimens taken. The occurrence of Diplocaulus is one of the most interest- 

 ing though not unexpected things. This genus occurs in the Illinois beds, 

 certainly at a lower horizon, but previous to the excavation of this bed none 

 had been found in the Wichita formation. 



There is a total absence of any remains of fish . Sharks would undoubtedly 

 have been attracted by the cadavers if there had been access to the pool 

 from the open water, and the presence of dipnoan and crossopterygian fishes 

 would certainly have been expected. The absence of these forms leads to the 

 suggestion that the place of deposit was a stagnant pool or perhaps a spring 

 or seep with an area of deep muck around it, in which the animals became 

 mired. Such an assumption throws some doubt upon the aquatic character 

 of Cricotus, which is so strongly indicated by the structure of its skeleton. 



Aside from the light thrown upon the structure of old forms, the nirmber 

 of new things which have come to light in the bone-bed is of great interest. 

 It is always to be expected that something new will be discovered in such 

 large accumulations, but the very considerable number of new things is 

 rather surprising. Unfortunately the new forms are represented by single 

 bones or by separate bones which can not be associated with certainty; for 

 this reason the author has not given new names to all, for there remains the 

 possibility that some of the bones regarded as indicating new forms may 

 belong to genera already described from fragmentary material. 



CRICOTUS. 



This genus is represented in the collection by abundant material of both 

 large and small individuals. The auth or has previously ^ suggested that but 



" Carnegie Inst. Wash. Pub. 146, p. 78. 



