ISSl.] ZuL [Stevenson. 



small block. Perhaps this should include also the concealed interval 

 below it. 



Nos. 24 and 25 are very similar to No. 21 ; they are granular, and 

 No. 24 is massive. No. 25 is more or less flaggy, and passes into a hard, 

 cross-bedded calcareous grit, which contains not a little chert. 



The limits of the two groups are. very distinct, and only a few feet at the 

 bottom of No. 25 mark the transition. Below that line, chert is present in 

 nearly every bed. Nos. 26, 27 and 28 are alike, except that very little 

 chert occurs in No. 27. Many layers of No. 26 are crowded with bryo- 

 zoans, and the smaller nodules of chert are casts of Productus. Crinoid 

 stems are abundant in No. 28, which is massive and clierty throughout. 

 No. 33 is well exposed in the railroad excavation ; its higher beds are dark 

 gray, streaked with white calcspar and contain much chert, some of which 

 certainly has replaced a ChcBtetes-Vike form. Fossils occur in the highest 

 beds, where sections of Productus, Athyris and Pleurotomaria? are abun- 

 dant ; the lower beds are massive,, almost black, and show only minute 

 fossils. No. 35 is very cherty in its upper and massive layers, but the 

 lower layers are somewhat flaggy, show little chert, and are crowded with 

 crushed fossils, chiefly Hemipronites and Athyris. No. 37 is flesh colored 

 to light blue, and is well exposed at the mouth of a hollow nearly half a 

 mile from the bridge over North Fork of Holston. There it describes a 

 short abrupt anticlinal, which is nicely shown in the railroad side-cutting. 

 This bed is the base of the upper member of the Silicious group. 



No. 38 is the Protean member of the Silicious group. It is not fully 

 exposed as the little hollow, already referred to, intervenes between the 

 last exposure of the limestone and the first exposure of this mass, the con- 

 cealed interval being perhaps 35 or 40 feet. But under the petty anticlinal, 

 the upper part of No. 38 is shown within 5 feet of the limestone, the inter- 

 val being filled with some drab clay, which may belong with either No 37 

 or No. 38. The upper part of No. 88, as far as seen, is a fine-grained sandstone 

 with smooth fracture, but this passes downward into shales containing a 

 bed which is highly carbonaceous. The rocks below are fine-grained sandy 

 shales with beds of blue calcareous sandstone or grit, very fine-grained and 

 breaking with irregular fracture. These are very similar to the beds .seen 

 in No. 1 of the section. It is possible that coal occurs in the concealed part 

 of this mass, for a coal bed is said to be present under the river directly oppo- 

 site the mouth of the little hollow. The onl}^ fossil seen in these rocks was 

 a fragment, which probably belongs to Leiorhynchus. 



These beds rest comformably on the Chemung, as already stated. 



The dip of the rocks varies. In No. 35 it is nearly 20 degrees ; in No. 25 it 

 is 33 degrees and the strike is N. 60° E. mag. ; but here the rate increases, 

 and in No. 24 it becomes 40 degrees, which is the prevailing rate of dip up to 

 within 300 yards of the mouth of Wolf creek, beyond which no measure- 

 ments were made. It is not at all improbable that a fragment of the 

 Quinnimcmt group remains on the high land between Abraham's creek 

 and Wolf creek. 



