438 ELIOT BLACKWELDER 
plain is represented in this part of the district these features may 
well be outliers of it. The topography on the west and south 
sides of the Laramie basin thus seems to correspond fairly well with 
that on the east, suggesting a common physiographic history for the 
several parts of the district. 
In the Laramie basin itself I have not been able to recognize any 
remnants of the Sherman or older surfaces, and in explanation of 
this I suggest on a later page that the basin has been excavated in 
the Sherman plain. 
Ww 
JSELM MT PRED M7. BOULDER RIDGE 
Fic. 6.—Section showing supposed relation of the Sherman surface to the present 
topography, near the south end of the Laramie syncline. 
The Leslie cycle-——As described above, the Sherman peneplain 
is represented by a series of flat divides between the valleys which 
cross the Sherman uplift. A study of these valleys on the topo- 
graphic map shows at once that their upper reaches are very different 
from the lower. On the eastern flank of the uplift the streams run 
in narrow canyons of considerable depth. Near their heads, however, 
the valleys are conspicuously open, broad, and flat-bottomed. The 
creeks meander considerably, and are bordered by broad meadows. 
These portions of the valleys are occupied by ranches, the meadows 
furnishing the hay for winter feed, while the cattle are pastured on 
the grassy divides between. ‘The mining village of Leslie is situated 
in such a valley. Since there is no difference in the rocks, there 
can be little question but that the two divisions of these valleys 
represent two distinct cycles of erosion. ‘The head of the valley is 
the older portion, while the canyon is the result of more recent 
rejuvenation. : 
It has been suggested that the Leslie valleys are not later in age 
than the Sherman peneplain, but that they are merely shallow open 
valleys in a very advanced age, and that the flat spurs between them 
are the subdued divides of the same cycle. I find it hard to reconcile 
