LIMESTONES OF WESTERN TENNESSEE 683 



the upper edge of a low bluff, ending at a cultivated field at the 

 mouth of a stream traversing a narrow valley. The base of the 

 bluff on the east side of Horse Creek, just north of the mouth of 

 this stream, is formed by crinoidal, massive limestone, apparently 

 belonging to the top of the Brownsport bed. Immediately above 

 is limestone and clayey rock containing, within 10 feet of the 

 base, Camarocrinus and a number of brachiopods belonging to 

 the Linden bed fauna. Among these are Dalmanella siibcarinata, 

 two forms, one coarsely and one finely striate, Rhipidoinella 

 oblata, Bilobites varica, Strophonella punctulifera, and Spirifer perla- 

 mellosiis. About 200 yards south of the locality just described, 

 on the same side of Horse Creek, is the Calybeate Spring. 

 Here the exposure of the Linden bed is at least 60 feet thick. 

 Specimens of Camarocrinus are abundant in the lower and middle 

 part. Two miles above the Calybeate Spring, in a gulley south- 

 east of the home of Cab Blount, on the east side of a branch of 

 Horse Creek, the Linden bed is overlaid by a trace of Black 

 shale, poorly exposed, followed by the Waverly. Within 10 feet 

 of the top of the Linden bed it contains specimens of Camaro- 

 crinus. 



Large exposures of the Linden bed line the northern side of 

 the Tennessee River for more than a mile east of Pyburn Land- 

 ing. Here was obtained the section described by Safford as 

 occurring opposite White Sulphur Spring. At the eastern end 

 of the exposures, west of the mouth of Bluff Creek, the expos- 

 ure of the Linden bed is loi feet thick. At the base of the sec- 

 tion there is a series of cherty limestones, 1 1 feet thick, contain- 

 ing a species of Chonostrophia 23™™ wide related to CJi. helder- 

 bergia, Rhipido?nella oblata, U?ici?iulus nucleolatus, Uncimdus ( Wil- 

 soniaf) schucherti, Meristella jneeki, and Dalmanites pleuroptyx. 

 Unequal erosion of the cherty limestone forming the Linden bed 

 has caused the formation of shelves at elevations of ii, 34, and 

 50 feet above the river. Camarocrinus occurs from the water's 

 edge up to the 50 foot level. At the top of this part of the 

 section, Camarocrinus is associated with Favosites conicus, Favosites 

 with a convex base covered by the epitheca, Pleurodictyum lenti- 

 ■culare, Rhipidomella oblata, OrthotJietcs wookvorthanus, Leptacna 



