298 Shuler — Dinosaur Trades in the Glen Rose Limesto 



ne. 



shallow depth in a brief period of time. If the waves were 

 cutting against limestone rocks, lime muds would be deposited 

 near the shore. On the other hand it is true that the muds in 

 question might have been chemically precipitated. There is at 

 present no critical test to distinguish detrital lime muds from 

 those chemically precipitated unless triturated quartz grains be 

 valuable for that purpose. 



If the dinosaur was wading near shore then, since the dip of 

 the beds is very gentle it would be necessary to think of the 

 seas of Glen Hose time as very shallow, extending over many 

 square miles but only a few feet deep, perhaps not more than 

 five to ten feet deep. Current action except under stress of 

 storm was probably slight; yet the brecciated zone at the top 

 of the section does show current action. Shell fragments up to 

 an inch in cross section were transported. 



There is still a further problem to be solved and that is the 

 position of the Trinity sands during the deposition of the Glen 

 Rose limestone. E-. T. Hill's position that the Glen Rose lime- 

 stone passes laterally into Trinity sands seems to be substan- 

 tiated by many facts. It is noteworthy that in the vertical 

 transition from Trinity sands into Glen Rose limestone there 

 are abrupt alternations of limestone and sand without interme- 

 diate shale beds. It seems quite probable that the lateral tran- 

 sition was equally abrupt and that while Trinity Sands were 

 being laid down along shore Glen Rose limestones were form- 

 ing near shore, so near in fact that only the transition beach of 

 Trinity sands and marls intervened. If such were the conditions 

 then it would have been easily possible for a land animal to 

 have waded out far enough in a shallow sea to have left tracks 

 in lime muds. 



Euhrontes (.^) titan opelopatidus sp. nov. 



For this lower Comanchian dinosaur track the following name 

 is offered: Euhrontes (?) titanopelopatidtis sp. nov., which 

 being interpreted is "the lime mud strider." 



Southern Methodist University, Dallas, Texas. 



