294 Shider — Dinosaur Tracks in the Glen Rose Limestone. 



Art. XXIII. — Dinosaur Tracks in the Glen Rose Limestone 

 near Glen Rose^ Texas ; by Ellis W. Shulee. 



The finding of dinosaur tracks is sufficiently rare that it is 

 worth while to record all new localities, and especially forma- 

 tions carrying snch tracks ; the unique occurrence of these 

 tracks in limestone rock seems to merit a somewhat detailed 

 description. Thanks for calling the attention of the writer to 

 the locality and for helpful discussion is due to Prof. J. D. 

 Boon of the Texas Woman's College of Fort Worth, Texas. 



The dinosaur tracks figured in illustrations 1 and 2 are 

 exposed in the flat bottom of a ravine near Glen Rose, Texas, 

 where they are locally known as the " bird tracks." The tracks 

 are found in a hard white limestone which forms the bed of 

 the stream. The layers immediately over the limestone are 

 less resistant to stream erosion and the stream has stripped 

 back to steep banks a flat bottom more than fifty feet wide, 

 one side of which is covered by stream gravel and sand. 



Eight tracks were found, five in the uncovered portion and 

 three covered bj stream gravel. The tracks show a uniform 

 step of 4 feet and 2 inches. The dinosaur was moving N.E. 

 and the tracks are directly in line, each step following consecu- 

 tively and not alternately from side to side. The tracks show 

 three toes with a measurement of 16 inches from the anterior 

 end of the middle toe to the heel and a width of ten inches. 

 Imprints of claws occur at the end of each toe. There is no 

 evidence of a fourth toe or dew-claw. All tracks are surpris- 

 ingly alike, there being small evidence of right and left foot. 



The beds in which the tracks are found are placed in the 

 middle third of the Glen Rose Formation, which belongs to 

 the Trinity division of the Comanchian. According to K. T. 

 Hill"^ the Glen Rose Formation has in this locality a thickness 

 of 315 feet. The middle third of the formation is composed 

 of thick and massive indurated limestone. 



Figure 3 shows in detail the section immediately above and 

 below the layer carrying the tracks. The measured section is 

 as follows : 



Section of Glen Rose Limestone where dinosaur tracks are found 

 near Glen Rose, Texas. 



a) Shell breccia, indurated. 89^ calcium carbonate.-. 1^ inches 

 h) Shale, calcareous; greenish yellow. Limy at the top 8 inches 

 c) Shale, greenish yellow. Weathers into a fine- 

 grained clay. 33^ calcium carbonate ._ 5 inches 



*21st Ann. Eept. U. S. G. S., pt. VII, p. 153. 



