moodie: armored cretaceous dinosaur. 259 



Granite mountains, on Connant creek ; in a small anticline west 

 of the Rattlesnake mountains ; along the northern and eastern 

 flanks of the Rattlesnake mountains. There are extensive ex- 

 posures on the eastern slope of the Big Horns, and I do not 

 doubt that they occur also to the west of these mountains. In 

 text-figure 1 is given a view of a typical exposure of the 

 Hailey shales, on Connant creek, north of the Granite moun- 

 tains, Wyoming. On the left of the photograph the Mowry 

 beds stand out in the characteristic ridge. 



The vertebrate fauna of the Hailey shales still remains to be 

 accurately determined, but so far as known it is represented 

 bj^ large and small fishes, amphicoelian crocodiles with hollow 

 limb bones, turtles with completely ossified carapaces and 

 plastra like Toxochelys and plesiosaurs of two types. The re- 

 mains of plesiosaurs are in places exceedingly abundant, evi- 

 dences of no less than fifty-five individuals having been dis- 

 covered during one summer. Occurring in these deposits, also, 

 have been discovered the remains of three dinosaurs. The re- 

 mains described below represent one of these animals. The 

 other two are known in one case from a single worn dorsal 

 vertebra found in one of the massive shell-concretions con- 

 sisting of myriads of gastropod and lamellibranch shells to- 

 gether with plesiosaur teeth and vertebrae, about ten miles 

 north of where the Stegopelta remains were exhumed ; and in 

 the other case from three caudal vertebrae discovered in the 

 same beds nearly a hundred miles to the east, near the western 

 base of the Rattlesnake mountains. 



The Stegopelta remains herein described were once encased 

 in one of the brown sandy clay concretions so abundant in this 

 formation, but many years ago it was exposed and by the 

 weathering processes of a long space of time had become re- 

 duced to hundreds of fragments. These fragments had washed 

 and rolled down the slope and had been trodden in the mud 

 by cattle so that when first discovered it was discarded as a 

 worthless plesiosaur specimen. When Doctor Williston, how- 

 ever, in cleaning up some of the fragments came across some 

 typical stegosaurian dinosaur teeth, the whole aspect of the 

 matter was changed and every fragment was carefully col- 

 lected. As boxed the specimen weighed only 450 pounds, of 

 which about two-thirds was bone. It has been a long and 

 tedious task to fit together the scattered and disassociated 

 fragments, but through the combined eff'orts of Doctor Willis- 



