Survey of the Concho Country. — Cummins-Lerch. 323 
its geological features. It constitutes a part of the Cretacic 
deposits known as the Gulf series. These deposits have been 
laid down by the Cretacic sea till a gradual elevation of the 
strata took place and the retreating waters left the former bot- 
tom of the ocean a part of the continent, a vast undulating plain. 
Concluding from the fact that these deposits are only covered 
by alluvium, no new subsidence has taken place in this coun- 
try, but the waters retreating have commenced to cut their 
channels and have so well succeeded that they have cut through 
the whole Cretacic series, and in their lower courses into the 
underlying Permian formation. The valleys are narrow at 
the beginning, gradually widening and deejiening till at their 
confluence, they form a valley not less than 30 miles in width. 
Plateaus, remnants of the former plain with gentle declivi- 
ties, changing frequently to abrupt escarpments of picturesque 
appearance, lie between rivers and creeks. 
Geologry. 
The geology of this country is the more interesting as three 
grand periods of our world's history are represented in the cir- 
cumference of a few miles. The Permian formation, the tran- 
sition period between the old and new forms of life, underlies 
the Cretacic, the last of Mesozoic time, which represents in its 
wide plains the accumulations of the Cretacic ocean. In these, 
diluvial floods have left their traces; deep and wide valleys, 
narrow canons, steep embankments, hills, ridges and huge de- 
posits of conglomerate speaking of the dawn of a recent period, 
and marking the prominent features of the present topography 
of this portion of Texas. Quiet waters succeeded, left in bas- 
ins and hollows by the retreating diluvial floods. The valleys 
had then a swampy appearance, covered with small lakes and 
lagoons in which modern life commenced to flourish, and 
through which the rivers wind their way, grinding the rocky 
material and transporting and depositing the fine sediment 
which at the present marks their courses, and is recognized by 
the geologist as loess deposits. It was left to alluvial times to 
drain gradually these many swamps and lakes, to form the va- 
riety of soils, to cover valley and plain with a dense turf of 
nutritious grasses, and people them with buffalo, antelope and 
Indians. Modern times have commenced to work out anoth- 
er change, tlie white man has replaced the Indian, cattle the 
