DEVON TAN ROCKS. V 
Section along Yellow Creek, in sec. 22, T. 1 N., R. 10 E. 
Feet. 
4. Thin-bedded, impure limestone at base, changing gradually to a bluish limestone at top of cliff 95 
'6. Compact blue limestone, nonfossiliferous 40 
2. Dark -gray limestone containing Tentaculit.es gyracanthus, Dalmanites cf. micrurus, Chonos-. . 
trophia sp.? Spirifer cyctopteris, Stropheodonta planulata, Leptsena rhomboidalis, Platy- 
ceras tenuiliratum, Anoplotheca concava, Dalmanites pleuropter, Rhipidomella oblata, Mer- 
istella arcuata, A vicula cf . subequilatera, Stropheodonta beckei, Chonoslrophia helderbergia. . 10 
1. Dark-colored, pure limestone containing Callopora cf . perelegans to water's edge 5 
Fig. 4.— Section from Gattman to Fort Adams. L, loess; K, Grand Gulf (sandstone and clay); 
J, Vicksburg (limestons) ; I, Jackson (clays and marls); H, Claiborne; G, Tallahatta (sandstone); 
F, Wilcox (sands and clays); E, Midway (limestone and clays); D, Selma (limestone); C, Eutaw 
(sands and clays); B, Tuscaloosa (sands and clays); A, Paleozoic (limestone, etc.). 
At the point where the public road crosses the creek in sec. 15, T. 1 N., R. 10 E., the 
dark-blue limestone occurs at the water's edge and extends to a height of about 50 feet. On 
the north side of the creek the contact between the dark-blue limestone and the thinner 
bedded shaly limestone passing into blue shale is studded with the following fossils, which 
occur in a thin ledge of silicified chert: Orthothetes woolworthanus , Rhipidomella subcarinata, 
Proetus protuberans, and many of the forms found in the above list. Owing to the detritus 
which has covered the hillside it was impossible to determine the thickness of this fossilifer- 
Fig. 5.— North-south cross section from Scranton to Tennessee River. L. Quaternary (silts); K, 
Grand Gulf; J, Vicksburg; I, Jackson; II, Claiborne; G, Tallahatta; F, Wilcox; E, Sucarnochee; 
D, Selma; C, Eutaw; B, Tuscaloosa; A, Paleozoic. 
ous horizon, but it is measured in inches rather than in feet. The same dark-blue limestone 
is reported to form the cliffs on both sides of the stream from this point to the mouth. 
In the northwest quarter of T. 2 N., R. 10 E., where the Iuka and Red Bluff Springs road 
crosses Yellow Creek, the limestone outcrops for one-half mile above the ford. At the " big 
rock" the limestone is horizontally bedded and when long exposed breaks down into thin 
shelly layers. It is a very compact, fine-grained, dark-blue rock, and, when freshly broken, 
gives a strong fetid odor. At about 30 feet above the creek at this point is a highly silicified 
bed of angular chert, or hornstone, destitute of fossils. 
