— 44 2 Cincinnati Society of Natural History. 
or-else the precipitous character of the side of the valley has altogether 
prevented their formation. The steps vary greatly’ in height, the 
greatest height observed being as much as one hundred feet ; in width, 
- from one to five chains is not uncommon. 
Nearly all the lakes in British Columbia occupy long, narrow de- 
pressions in the river valleys, and are, in fact, lake-like expansions of 
the rivers. There is no doubt that such lakes were at one time much 
more extended and more numerous than they now are; and that, in 
many places, as, for instance, at Lytton, and on the north bend of the 
Thompson, and at Canoe river crossing, the terraces mark the old 
margins of these lakes, while in others they doubtless represent only 
the ordinary flood-flats of the rivers. The removal of the rocky bar- 
riers by which these inland waters were confined would result in the 
formation of such gorges and canons as we now find on the Fraser at 
Gale, and below Lytton, as well as on the North Thompson at Murehi- 
son’s Rapids, and on Canoe river below the wide flats at the crossing, 
and would, without any general movement of elevation, drain off the 
waters of the lakes, leaving the old shore lines exactly as we now see 
them, at corresponding heights on both sides of the valleys. Ordinary 
alluvial river flats do not commonly occur in that manner, but where 
a flat occurs on one side there is usually a steep bank on the other, 
and especially is this so along rapid rivers which traverse a mountain- 
ous country. 
Dr. F. V. Hayden* said, that Fort Bridger is located in what appears 
to the eye a sort of basin, inclosed by high, arid table lands, but really 
in a central portion of the drainage of Black’s Fork. The beautiful 
valleys, Smith’s, Black’s, and Muddy, have been carved out of the 
horizontal strata, and between the streams are terraces and flat table 
lands, which give a singular outline to the surface of the country. 
No forces now in operation, in this vicinity, could have given the ex- 
isting features to the surface of the country, and the cause must have 
been local, proceeding from the northern slope of the Uintas. The 
beautiful table-top divides between the valleys, and streams are exten- 
sions into the plains of the radiating ridges of the mountain slope, and 
are literally paved, in many places, with the water-worn bowlders 
of the purplish sandstones and quartzites, and with the carbon- 
iferous limestones that compose the nucleus of the Uintarange. Here 
and there we can see a flat-topped butte cut off by erosion from some 
of the intervening ridges, and rising above the surrounding country as 
* U.S. Geo. Sur. of Wyoming. 
