254 TRANSACTIONS OF THE [may 18, 
Uintahs and emerges into the low lands of the Uintah Valley. 
It is a valley along the eastern portion of this bend in Green 
River that has received the name of Brown’s Park. (See Plate 
XVIII.) 
Along the axis of the Uintah Mountains, which have a nearly 
east and west tend, is exposed the hard, metamorphosed sand- 
stone, known as the Weber quartzite or Uintah sandstone. At 
the eastern extremity of the range this exposure divides, send- 
ing out two long, eastwardly projecting spurs, one of which 
passes along the northern, the other along the southern border 
of Brown’s Park valley. Of these the southern is by far the 
broadest and forms the real axis of the range, while it is at the 
same time much the longer of the two. We havethus a roughly 
outlined valley somewhat resembling the letter U, tilted on one 
side with its open end towards the east and the upper arm some- 
what shorter than the lower. 
Across the open end of the U runs the low divide that sepa- 
‘rates the drainage areas of the Green and Little Snake rivers, 
while between this divide and the upper, shorter arm flows Ver- 
milion Creek, a stream which must have played no inconsider- 
able part as a silt bearer in the formation of the Brown’s Park 
beds. 
To the north of the mountains lie the Bridger and Washakie 
basins, where the entire series of Eocene tertiaries are exposed, 
but most noticeably the beds of the Bridger epoch. These two 
basins are drained, the one by the Green river and the other by 
Vermilion creek and it seems probablé that these formations 
furnished much of the material of which the beds in Brown’s 
Park are composed. 
The last named beds themselves come in contact with two 
formations in the valley and perhaps a third at the open end. 
The first is the Weber quartzite before mentioned and it is 
directly against the eroded flanks of this hard rock that the 
Brown’s Park is seen to rest. 
The second is a narrow strip of Green river shales which 
sweeps around the upper arm of the valley and runs along its 
northern edge, forming what is known as O-wi-yu-puts Plateau. 
These shales dip to the south from 18° to 25° and can be seen 
passing unconformably under the Brown’s Park. 
The third formation is perhaps a portion of the Green river 
shales or it may be another and later tertiary. It forms the 
divide between the drainage areas of Little Snake river and Ver- 
milion creek, which we shall for convenience call the Snake 
river divide. This divide is, however, so covered by accumula- 
tions of soil that the true relations of the beds within the park 
