white.] AYASATCH FOSSILS FROM WHITE EIVEE VALLEY. 227 



ining is more spinous and otherwise more strongly marked than any ol 

 those other forms which have received separate speciiio names. The ex- 

 amples of this species found in the valley of White River are large, 

 some of them being more than two inches in length, and correspond 

 with Hall's figure and description of the variety nodulosum more nearly 

 than the other varieties do. 



5. Viviparus paludinmformis Hall sp. 



This species was described in the same report together with the pre- 

 ceding species under the name of Turbo paludincej vrinis. It is a constant 

 associate of Goniobasis tenera, and at none of the very many localities 

 where I have collected these two species I have never found either of 

 them unaccompanied by the other. This species varies comparatively 

 little, even in the different groups in which it has been found. Only oiie 

 other species of the genus has yet been found in either the Wasatch, 

 Green River, or Bridger Group. This is V. icyomingensis Meek, which 

 has been found only in the Bridger Group. V. paludikaformis appar- 

 ently ranges up iuto the lower portion of the Bridger Group. 



The fossil iferous horizon that furnished the fossils of the foregoing 

 list was also found among the upturned strata of Raven Ridge, west of 

 Raven Park. The ridge has its southeastern end at the western sio/e of 

 Raven Park and its northwestern end near Section Ridge, a spur' of 

 Yampa plateau. In the upper portion of the Wasatch Group, near rhe 

 northwestern end of Raven Ridge, I obtained an abundance of speci- 

 mens of Goniobasis tenera and a few of Viviparus paludinmformis. Near 

 the southeastern end of the ridge and at the same horizon I obtained a 

 few examples of both those species together with some of Unio washa- 

 teensis and JJ. shoslwnensis. The Green River Group is abundantly 

 shown in this region, in ell the peculiarities which characterize the 

 group at its typical localities, and yet no distinct plane of demarkation 

 or place of separation between it and the Wasatch Group could be any- 

 where recognized. 



While passing down the valley of White River from Agency Park to 

 Raven Ridge the strata of the Laramie Group came frequently under 

 observation. They were there found to possess all their usual lithologi- 

 cal characteristics, and also to contain the great abundance of plant 

 remains that was observed in the Danforth Hills. The only invertebrate 

 fossils, however, that were found in its strata in that region were occa- 

 sional examples of Ostrea glabra, which was found to range nearly to the 

 base of the group. Directly north of Raven Park and about midway 

 between White River and Midland Ridge I found numerous examples 

 of Halysites major Lesquereux in layers that belong either to the base of 

 the Laramie or to the top of the Fox Hills Group. The horizon is doubt- 

 less precisely the same as that at which this fucoid occurs at the mouth 

 of the Saint Vrain's and elsewhere in Eastern Colorado. 



From a point on White River about twenty miles below Raven Park 

 I crossed to Section Ridge over the broad bad-land district that lies to 

 the northward. The dip of the Green River strata which border the 

 lower portion of Yv T hite River Valley is gently to the northward where 

 I traversed them. About eight or ten miles north of White River I found 

 them to pass beneath characteristic strata of the Bridger Group, con- 

 taining fragments of mammalian and chelonian remains. These Bridger 

 strata occupy only a very small area of surface in the immediate valley 

 of lied Bluff Wash, and are overlaid by the strata of the Uinta Group, 

 which occupy the greater part of the surface of this bad-land district 

 bordering Green River Valley. They rest unconformably upon strata 



