284 The American Geologist. Xl,v "" ll, " r ' 1903 - 
Besides the inner valley deposits, several bench deposits 
were laid down. One of which covers^ a large area northwest 
of Fort Apache in a bay-shaped flat surrounded by mesas and 
mountains and volcanic butte's. The sediments of this patch 
present some striking peculiarities. They are deposited upon 
a lava sheet which flowed down the valley from the north, 
dammed up the outlet of the river south of Kelley's butte, and 
then formed a great lava lake. This area, when the lava was 
cooled, was still laked by the lava in the river channel and in 
the lake this Post-glacial material was deposited. Another 
peculiarity is that three cobble-stone ridges run paralled to each 
other in a north and south direction the full width of the de- 
posits. They resemble lateral moraines in appearance but on 
examination no stria? markings were found upon any of the 
rocks, so we must look for some other explanation than glacial 
to account for their occurrence. If the channel of White river 
was blocked at the time of the deposition, as there is every evi- 
dence to believe that it was, outside of absolute proof, the 
streams entering the laked region from the north w r ould have 
force enough, even with the fall that the streams of the region 
have today, to carry or roll the cobble stones far out into the 
lake and, if it was shallow, to roll them to the opposite shore. 
In this way the ridges were probably produced. They might 
have been produced in the same manner even if there was no 
laked area, provided there was not flow enough to extend be- 
yond the flat surface area to cut a channel. 
In the Post-glacial might also be placed the travertine de- 
posits of the region. They represent the action of extinct 
springs ; springs which were most active in the interval between 
the last lava flow and the Post-glacial deposition just men- 
tioned. The largest of these spring-deposits is that of Elsesa on 
the west side of Xorth Fork about six miles above the White 
River post-office ; and the next in size is on little Cibicu creek, 
about seven miles northwest of the Indian farmer's residence 
on the Cibicu. The deposits of each are linear in shape. The 
latter covers an area of forty acres and the former eight hun- 
dred. The little Cibicu deposit is without any spring in its 
immediate vicinity, though the Grasshopper springs are some 
three miles farther up the creek. The Elsesa has but one sp-ing 
connected with it now and it is not a tavertine depositing 
