328 The American Geologist. 
June, 1905 
body of water ; but the presence of such beds has not been 
indicated. 
To the writer it appears that this basin formed in 
Bridger times a nearly level country, through which per- 
haps many streams, which had their origin in the surround- 
ing high lands, now the Uinta and Wasatch mountains, 
were flowing to some outlet. The basin had only a moder- 
ate slope, and was probably covered with vegetation, most 
probably a forest. The great mass of the materials was 
probably deposited during overflowing of the streams ; and 
thus was produced the stratification everywhere observed. 
As might be expected, the character of the materials changes 
within moderate distances. Under such conditions of de- 
position, the coarser materials, pebbles and sand, would be 
dropped in the beds of the streams, the finer materials over 
the flood-grounds. Through the choking up of the chan- 
nels by the accumulation of coarse debris and through other 
causes, these streams would often be forced to abandon 
their beds and cut new ones. The old channels would 
then become covered up; and at a later time, when erosion 
had done its work, many of these old channels would be- 
come exposed. One of the things which especially struck 
the writer in his peregrinations over and among the buttes 
of this region was what appeared to l)e the remnants bf 
some of these old river-beds. Sometimes they appear as 
masses of sandstone many feet high, with the finer and 
more clayey layers coming up al^ruj^tlv against their nearly 
perpendicular sides. Now and then one would be found 
emerging from the side of a butte and reappearing farther 
on in the side of a neighboring butte. 
As the writer returned from \\"yoming he was im- 
pressed by the conditions along the Platte river, a broad 
and shallow stream, nearly on a level with its flood-ground. 
This it must often overflow ; and over this flood-ground it 
must wander about in ever changing channels. At that 
time the Kansas river had l)een overflowing its banks, and 
here and there, in the region about Lawrence. Kansas, old 
and al)andoned river channels were again filled with water 
and appeared as temporary lakes far away from the present 
river. Should there occur at some future time in this re- 
