LIMESTONES OF WESTERN TENNESSEE 583 



interval of 22 feet separates the limestone from the Hardin 

 sandstone. 



A very instructive exposure occurs on the hillside rising 

 above the northeastern part of the cluster of houses known as 

 Martin's mill. Here the sandy Gant limestone (Layer A) is 

 found 57 feet above the road, and about the same distance above 

 the Dixon bed. It is 5 feet thick and forms a projecting ledge. 

 Overlying it is found a bluish, better bedded limestone, partly 

 fine-grained and partly crinoidal, g feet thick (Layer B). Fol- 

 lowing this is more limestone, much weathered and poorly 

 exposed, 14 feet thick (Layer C). 



The whitish clays and soft limestones beneath the Gant lime- 

 stone contain the sponges, brachiopods, and crinoids character- 

 istic of the glade exposures of the Brownsport bed. At the A. 

 B. Gant locality, the Gant limestone contains Spirifer saffordi, 

 Dictyonella gibbosa, Niicleospira concentrica, Wilso?iia saffordi, Unci- 

 nulus stricklandi, and Orthothetes subplanus. Some of these fossils 

 occur also in the Gant limestone at the northeastern edge of 

 Martin's mill, and at various exposures along the northern bank 

 of Indian Creek, down stream. 



In the overlying, more distinctly bedded limestone, Layer B, 

 at Martin's mill, are found Wilsonia saffordi, Uncimdus strickla?tdi, 

 Orthothetes subpla?ius, Gypidula roemeri, Camarotoechia neglecta, 

 Nucleospira concentrica, and Meristina maria roemeri. 



In the poorly exposed limestone at the top of the section, 

 Layer C, occur Astylospojigia praemorsa, Caryoma?ion stellatini-sid- 

 catum, Meristina maria roemeri, and Wilsonia saffordi. About a 

 mile below Martin's mill, northwestward, on the northern side of 

 Indian Creek, Caryoma?io?i incisolobatiim was found within a foot 

 of the Hardin sandstone. 



A. F. FOERSTE. 

 \To be continjied.^ 



