330 proceedings: geological society 



The fossil evidence is partly in harmony and partly at variance. 

 The Lance contains a Triceratops fauna, but the Lower Laramie has 

 been supposed to be entirely barren of dinosaur remains; however, 

 dinosaurs occur in it. Fragments of bones collected near the mouth 

 of Little Medicine Bow and west of Rawlins, about 2000 feet above the 

 top of the Lewis and near the same horizon as some of the Triceratops 

 zones in Natrona County, were identified in one case as ceratopsian 

 bones and in the other as dinosaurian. Triceratops has been collected 

 from the lower 1000 feet of the Upper Laramie. This is evidence 

 that the Lance is equivalent in age to the lower part of the Upper 

 Laramie, or perhaps that Triceratops has a greater stratigraphic range 

 than hitherto assigned, or that faunal zones do not coincide with litho- 

 logic boundaries. The invertebrates, Tulotoma thompsoni and other 

 fresh or brackish water shells, occur in the Lance and the Lower Lar- 

 amie. The plants in the Lance as well as in the Upper Laramie are 

 stated to be of Fort Union age, and those in the Lower Laramie of Cre- 

 taceous age. The Fort Union flora of the Lance has come chiefly 

 from the upper half of the formation in the Dakotas and Montana, 

 but not from the type Lance in Converse Count}'' or the Lance of 

 Natrona County, while that from the Lower Laramie in Carbon County 

 has come in most cases from the very base or from the lower 2000 feet 

 of the formation. This may make some difference in our views regard- 

 ing the character of the flora, because this series of beds may range 

 up to 6000 feet thick. Most of the leaves that have been collected in 

 Natrona County from the base of the Lance have Cretaceous affinities. 

 Some leaves collected 600 feet above the base of the Lower Laramie 

 have Fort Union affinities. With so much of the Lower Laramie 

 removed by erosion from the syncline east of Walcott, it is easy to see 

 that the Fort Union species which exist elsewhere in the upper part 

 of the Lower Laramie and the Lance may have been missed at that 

 place. The present status of facts does not warrant correlating beds 

 mapped as Lance in Natrona and Converse counties wholly with 

 the Upper Laramie, but, on the contrary, they should for the most 

 part, if not entirely, be correlated with the Lower Laramie. 



W. B. Heroy: The relation of the Upper Cretaceous formations of 

 southern Wyoming and northeastern Colorado. The upjjer part of 

 the Upper Cretaceous section in Carbon and Sweetwater counties 

 in southern Wyoming has been described as containing the following 

 formations: Steele shale, 4000 feet; Mesaverde formation, 2000 feet; 

 Lewis shale, 500 feet; Lower Laramie, 1000-6500 feet. The Steele 

 shale is correlated with the upper part of the Mancos shale of Colo- 

 rado and Utah and with the lower part of the Pierre shale of the Great 

 Plains region. The Mesaverde formation consists generally of two 

 prominent sandstone members separated by a series of softer shaly 

 beds, the lower being approximately equivalent to the Parkman sand- 

 stone and the upper to the Teapot sandstone of central Wyoming. 

 , The Lewis shale is widely distributed over southern Wyoming and 

 northwestern Colorado. It has been recognized by Hares in his work 



