434 Correspondence. 
Their upper strata near Colorado City include only a few fragments of an 
undetermined shell four or five inches long, presenting a close affinity to 
an Inoceramus. In the same bed a fragment of a fish spine was also ob- 
tained. 
The exposed strata in the bluffs at Colorado City include — 
1. Eight feet of calcareous conglomerate. 
2. Forty feat of gray sandstone. 
3. Fifty feet of red beds of sandstone and shale. 
4. Twenty-five feet of thickly bedded brown sandstone to the edge of water in 
Colorado river. 
This section will serve to show the prevailing character of the rocks 
along the Colorado river in Mitchell county. Fifteen miles north the lower 
brown sandstone contains silicified wood of some coniferous tree. On Wolf 
creek, and near Colorado City, the fossil wood was found, in a small quan- 
tity, carbonized and forming a pure lignite. The presence of this lignite in 
isolated sticks has caused some prospecting for coal, which, of course, re- 
sulted in a failure. The beds of brown sandstone, in many places, grade 
into a conglomerate, which is sometimes loosely cemented, but at other 
times is very firm and strong. 
Owing to the frequent occurrence of the crumbling conglomerate, the 
country is in many places covered with numerous water-worn pebbles, 
leached out from those beds. 
Lone Wolf Mountain, in the north-east part of the county, is a hill which 
rises above the adjacent gently sloping plain about 100 feet, and forms a 
very prominent landmark that can be seen 25 miles distant. Its top ex- 
poses 16 feet of a hard firmly cemented pudding-stone, including various 
colored quartz pjbbles, the rock chiefly cemented by iron oxide, and so 
well cemented that, when broken, it forms a smooth fracture through the 
pebble, which breaks with no greater difliculty than the cementing ma- 
terial. This rests upon two feet of ferruginous quartzite, and below it for 
over 80 feet, extending to the lower plain, we find occasional outcrops of a 
dirty drab sandstone. Near the mouth of Champion creek, on Colorado 
river, we find on the hill-top fragments of a drab-colored flaggy limestone, 
with some blue chert, containing a few obscure remains of Cretaceous fos- 
sils. Next below it is 40 feet of conglomerate, with some sandy beds; then 
50 feet of red beds — chiefly deep red sandstone, — with some shale beds, 
some of them beautifully ripple-marked. Flakes of gypsum are occasion- 
ally intercalated. 
On the higher lands are found, at many places, fragments of limestone 
like that found at this place — all going to show it to be the highest rock in 
the county. 
The connection of these beds with the overlying Cretaceous was obtained 
on Silver creek in Nolan county, 12 miles from the Colorado river, as fol- 
lows: 
1. <D r Eleven feet ash-drab limestone, containing Ammonites peruvianus. 
2. o Fifteen feet drab shelly limestone, abounding in Bjcofi-yra texana. 
3. '^ J Seven feet of limestone with a few fossils. 
4. ■£ j Four feet of brown shelly limestone, abounding in fossils, including (?ry- 
O t pbsea pitcberi, (small var.), Ostrea anomieeformis, Globiconeba, etc. 
