596 CHARLES S. PROSSER 
SECTION ON EASTERN BANK OF ROCKY FORK 
Total 
No. Thickness Thickness 
Feet Feet 
5. Gray, fine-grained, quartz sandstone ae in 
thickness from 4 in. to 1 ft.. eee Seo ores 6 
4. Bluish shales which are quite arenaceous nd con- 
tain some small sandstone concretions. These shales 
only slightly resemble those of the Bedford........ 315 5 
3. Bluish-gray, compact, fine-grained, quartz sand- 
stone, from 4 to 6 in. thick. This layer in places has 
concretionary structure and again it is broken and 
displaced. In former section given as the basal one 
of thesbereanOrmaatiOnet rg inert ret “py Ite 
2. Blue shales with some thin, sandy layers, the thicker 
ones ripple-marked. Zone varies from 11 to 16 in. 
iTaEHICKTESSnsetiees ae acne eae rel tee ce asen ere Tes 1% 
1. Compact, blue, fine-grained and thin-bedded sand- 
stone which is ripple-marked and is 1} in. thick. 
This is a somewhat calcareous sandstone, as may be 
seen from the analysis, with a texture somewhat like 
the» Bedtord:sandstonese = so-so ee ae 
a|_ 
aH 
| 
ol 
These three sandstones were analyzed by Professor D. J. 
Demorest with the following result: 
Zone No. 3 
Zone No. 1 (Former Base of Zone No. 5 
Berea) 
Per cent Per cent Per cent 
CaCO piase yore area Rear 1.4 0.8 
Me CO ir cieunm ce Segue 1.8 (),(0) 0.0 
HELO Weer cine icine eee 4.4 2.0 2.0 
IO) he un ck eau orate ees O22 0.2 0.2 
(CIE Nader sc nieta ints Hate rears 18.5 13.4 i083.) 
Quantzrer iinet ae 59.0 66.0 66.0 
iHeldsparmrewi- croc t ierac 10.0 17.0 18.0 
It will be seen from the above analysis that the calcium and 
magnesium carbonates (6.9 per cent) of zone No. 1 are lower than in 
the other analyses of Bedford sandstones of this region, while the 
amount of quartz is not greater than in some of them. In the two 
higher sandstones the amount of CaCO; diminishes from 1.4 per 
cent to 0.8 per cent, while there is no MgCO; and the quartz has 
= American Geologist, XXXIV (1904), 340, footnote, No. 2 of section. 
