7 + 
The American Geologist. 
Feb. u 
width which is still widening towards the easl when' they have un- 
covered the underlying Carbonic rocks. Hack waters have cut 
deep channels into the retreating Cretacic, and es- 
pecially prominent of these is the South Concho 
river with a length of about forty miles. The 
larger number of these rivers and creeks are fed 
by bold springs. Love creek, for instance, breaks 
from the Cretacic rocks, a ready stream not less 
than twenty feet wide by one and admit' feet in 
depth. The South Concho river and Spring creek 
have their sources in a number of springs of arte- 
=.i sian character, located in the center of shallow ba- 
Ei sins of considerable size. That the deep and wide 
\ ccSc valleys of the Concho rivers cannot have been 
Sri-* formed under the present climatic conditions but 
have been worn out by greater volumes of water, 
-? probably the inland sea which once covered the 
g '-staked plains," has been referred to in the paper 
.§ mentioned above. lb T. Hills •• Staked Plain 
•f- Series " covering the Cretacic of that western section 
g p of Texas, and consisting of beds of more recent 
~ "§ origin, seems to prove conclusively the existence of 
'f £ such a sea in post-Cretacic times. Huge deposits 
^ | of conglomerate composed of material derived from 
"! .^ the adjacent Cretacic strata, accompanying the riv- 
£'§* ers and creeks along their course even after their 
8 J continence below the city of San Angelo for miles, 
gj and the lower dip of the underlying and adjoining 
S£ deposits, appearing almost in :i horizontal position, 
. . and which never have been disturbed by violent, 
volcanic eruptions, speak of vast volumes of water 
which have broken the hard Lower Cretacic lime- 
stone deposits to fragments and have rolled the 
blocks before them, till, on reaching the older form 
ations with their opposite dips and consequently 
increased resistance, they have slackened their swift 
current, grinding the material liner and spending 
their energy in widening their bed. The large fragments of con- 
glomerate of cemented materials of every size, large blocks and 
