434 A. F. FOERSTK — LIMESTONES OF TENNESSEE AND KENTUCKY 



At South Tunnel about 8 feet of the la3'ers near the top of the Ordo- 

 vician appear contorted (plate 37, figure 1). What produced this ap- 

 pearance is unknown, the contortion affecting the middle parts of the 

 layers without preventing a fair degree of evenness on their upper and 

 lower surfaces. The same aj^pearance is noted in the beds immediately 

 beneath the Clinton west of Whites Bend (plate 39, figure 1). A litho- 

 logicall}'' similar rock occurs below the 4 feet of limestone belonging to 

 the Leipers Creek bed at Bakers station. According to this, the equiva- 

 lents of the marble in the Leipers Creek valley and of the dyestone at 

 Bakers station will not be found at Whites Bend or at South Tunnel. 



THE CUMBERLAND SANDSTONE OF SOUTHERN KENTUCKY 



Origin of the name. — A group of nearly unfossiliferous rocks occurs in 

 southern Kentucky, beneath the Black shale. Tliey extend from the 

 southwestern border of Pulaski county to the southern limits of the 

 state, and were called by Professor N. S. Shaler the *' Cumberland sand- 

 stone." The name sandstone is inai)propriate, because the rock varies 

 usually between a calcareous clay and a clayey limestone. Since the 

 most eastern exposures of Ordovician rocks do not quite reach the Pu- 

 laski county boundary, it is evident that all practically unfossiliferous 

 beds were included under this name. 



These Cumberland beds and the underlying rocks were so much 

 folded and eroded i)revious to the deposition of the Black shale that the 

 same layers occur at difierent depths beneath the Black shale at dif- 

 ferent localities. There has also been much folding since the deposition 

 of the Black shale. 



The Folder limestone. — Although the general mass of the Cumberland 

 bed is practically unfossiliferous, there is one horizon at which fossils 

 are fairly constant for a considerable distance. On account of its ready 

 accessibility east of the store at Fowlers landing, on the side of the hill, 

 it will prove convenient to refer to this horizon as the Fowler limestone. 



About a mile above Burksville, on the south side of the river, in 

 a gully which rises steeply eastward from a spring at the river's edge, 

 the Fowler bed occurs 44 feet below the base of the Black shale. At the 

 top is a layer of dense limestone 1 to 1.5 feet thick. Below is shaly 

 bluish limestone 1 foot, with Hehertella occidentalism Pterinea demissa, and 

 Ischyrodonta near elongata. Beneath is a limestone layer with branching 

 bryozoans. The bed occurs 1 10 feet above the river. 



Just above the mouth of Rennix creek the Fowler bed occurs 56.5 

 feet below the Black shale. At the top is a dense limestone layer con- 

 taining Ischyrodonta near elongata; below are 2 feet of dark shaly or 



