LIMESTONES OF WESTERN TENNESSEE 575 



place. — Three localities belonging to the Brownsport horizon 

 were referred by Professor Safford with some hesitation to the 

 Helderbergian or Linden limestone.' These are Bath Springs, 

 the Colonel Smith locality, and the A. B. Gant locality. 



The Bath Springs are located about a mile and a half east of 

 Martin's store, and about the same distance northwest of Martin's 

 Landing; the springs are situated in the valley south of the home 

 of W. N. Davis, and the Silurian exposures occur north of the 

 house. The top of the Dixon bed occurs 67 feet above the level 

 of the springs ; it is the top of the Variegated bed of Safford. It 

 is overlaid by shaly limestone, 17 feet thick, containing Astraeo- 

 spongia meniscus (Layer A); hard limestone, 4 feet thick; white 

 clay and soft limestone, 22 feet thick (Layer C), containing the 

 fauna investigated by Safford ; hard limestone, 7^ feet thick; 

 softer layers of rubble limestone, 19 feet exposed, containing 

 Caryomanon, stellatint'Stdcatum, Fistidipora hemispherica, Entero- 

 lasma wayiiense, and Rhipidomella saffordi. The Silurian is immedi- 

 ately overlaid by the iron-ore gravels of Safford. The absence 

 of the Helderbergian at the Rise mill and at Lego makes it pos- 

 sible that it may have been absent in times preceding Tertiary 

 erosion also at Bath Springs. 



The Colonel Jim Smith locality is situated about 9 miles east 

 of Savannah on the road to Waynesboro. The property now 

 belongs to John Godwin. The exposure consists of clay and 

 soft limestone covering the slope between the house and the 

 road, and extends for a short distance both east and west along 

 the road. Numerous brachiopods characteristic of the Browns- 

 port horizon occur. The absence of the sponges so characteristic 

 of the Brownsport bed at many localities probably caused the 

 difficulty in the identification of this bed. About a mile west of 

 the Colonel Smith locality, east of the home of Jim Irwin, numer- 

 ous corals associated with Astylomajwn vernicosuni are found along 

 the road. Half a mile farther, west, east of the home of Georg-e 

 Wilson, the brachiopod fauna seen at the Colonel Smith locality 

 is associated with Astylomano7i verrucosurn, in a bed of whitish 

 clay and soft limestone. Half a mile westward, in front of the 



'Geology of Tennessee, par. 849. 



