THE UPPER TRIASSIC OF WESTERN TEXAS. 



83 



These vertebrae must be tentatively assumed to belong to a small Dinosaur, such 

 as bore the skull, the posterior portion of which is described above, as the sizes of the 

 two specimens correspond very closely, and as they were found in the same beds and but 

 2 or 3 miles apart. Until further evidence is 

 found, the vertebrae may be assigned to the 

 genus Caelophysis. 



A femur, No. 3396, University of 

 Michigan (fig. 32), is rather puzzling. It is 

 42.16 centimeters in length. Compared with 

 a typical phytosaurian femur (No. 3395), it 

 is much heavier at the articular ends and the 

 articular surfaces are better formed. The 

 relation of the long axes of the articular ends 

 is different in the two forms; in No. 3395 

 the axes are nearly at right angles, so that 

 when the head was in the socket of the pelvis 

 the anterior face of the lower end was pre- 

 sented almost directly forward; in the second 

 femur the axes are at an angle of 60°, so that 

 the anterior face of the lower end was pre- 

 sented inward as well as forward. 



In the phytosaurian femur the tro- 

 chanter has the characteristic form of an oval 

 elevation with a depressed center, and the 

 lower end has a simple articular region ob- 

 scurely divided into two parts. In the other 

 femur the trochanter is simply a heavy rugose 

 area but little raised above the rest of the 

 bone; the lower end is heavy and divided 

 into two areas, but on the posterior side of the A - Wt """""J • Dmosa " r > front view > No. 3396. 



., ' ... U. of Mich. X 0.25. 



outer part there is a prominent process which u. Posterior view of same 



is continued upward on the shaft of the bone 



as a ridge for some distance. This femur has a very dinosaurian aspect, resembling 



in many details the figures of the femora of Plateosaurus and Gressylosaurus from the 



Triassic of Europe, and, so far as can be determined, the femur of Anchisaurus from the 



Triassic of North America. No remains of Dinosaurs of the size indicated by this femur 



have been found in the Triassic of the western portion of North America; Coelophysis 



Cope was decidedly smaller. It is to be hoped that more material revealing the skeleton 



of this Dinosaur will be found. 



Fig. 32. 



COPROLITES. 



There are several types of coprolites contained in the collection. The number found 

 in the Holmes Creek region is very large and the condition of preservation is in most 

 cases very good. 



The first type is that which must be assigned to the larger reptiles and stegocepha- 

 lians. These vary from 5 cm. in length to as much as 15 or 18 cms. The form is generally 

 regular, with smooth surfaces. In none that have been found has it been possible to 

 detect anything, such as comminuted bones or scales, that would indicate the nature 

 of the food. Microscopic sections have not been made of any of the coprolites. 



