76 The American Geologist. Feb. isdi 
which leave no doubt that these and the strata below are of Per 
mian origin. 
Above this fossil i Tenuis limestone rests a quartz conglomerate 
about twelve feet thick. The pebbles are well water-worn, ol 
small size and bound with a siliceous and irony cement. Tin 
conglomerate is stratified, dips towards the northwest under a 
steeper angle, however, than the underlying Permian deposits, 
and is occasionally interspersed with large blocks of given and 
red speckled quartzyte. The conglomerate is very hard, takes an 
excellent polish and is of a yellowish-red color. Above it lies n 
series of red and yellow colored clays and sandstones about one 
hundred feet thick, overlaid by lighter buff and whitish colored 
thin beds of loose .friable sandstone and clays about fifty feet thick, 
followed unconformably by the Trinity sands. I have called this, 
complex of strata commencing with the quartz conglomerate and 
overlaid unconformably by the Trinity sand ;i southward thinning 
out of the Jura and Trias on account of its lithological character 
and stratigraphic position, not having been able to find fossils foi 
confirmation. Along the Colorado river about thirty miles north 
of San Angelo gypsiferous strata arc 1 exposed above the beds de- 
scribed. U, T. Hill, in speaking of the Trinity sands, remarks:* 
" The writer has made sufficient observations to prove beyond all 
doubt that they are newer than the gypsum-bearing beds of Texas 
and that there is a stratigraphic nonconformity between them, as 
seen at Sweetwater mountain, Xolan county. Texas, and at Tu- 
cumcari mountain in general lithological appearance and 
in occurrence of saurian remains, these beds bear striking resem- 
blance to the Atlantosaurus beds of Canyon City, Colorado, and 
Como, Wyoming." It has been justly remarked that the strati- 
graphic position of a series of beds even when different in litho- 
logical character from the underlying anil overlying deposits alone 
does not prove their age and so long as there are no fossils found 
and described the age of the enumerated strata may not be con- 
sidered conclusively determined. However, this characteristic 
conglomerate indicates a total change in the topography of this 
section at the close of the Permian, and doubtless has been formed 
by strong currents along a coast line. The quartz pebbles consti- 
tuting it, though small and well water- worn, still enclose large blocks 
♦Arkansas Geological survey, Annual Report, vol. ii. 1888, p. L25. 
