LIMESTONES OF WESTERN TENNESSEE 701 



but upon the entire fauna. This will require further collecting. 

 I desire here merely to call attention to the fact that even within 

 the limited exposure at Clifton the supposed Warren bed runs 

 out southward, and that this exposure also presents the thickest 

 Richmond section so far discovered along the Tennessee River. 



Recently Mr. Ray S. Bassler has identified Hemiphragma 

 imperfectum, a characteristic species of the Upper Richmond in 

 Illinois, from the coarse, cross-bedded ferruginous rock at the 

 base of the Silurian section at Iron City. This necessitates also 

 the reference of the cross-bedded, less ferruginous rock at the 

 base of the Silurian section at Riverside to the Upper Richmond, 

 the Clinton at both localities consisting of less than i foot of 

 silicious or cherty limestone. The coarse conglomerate, half a 

 mile east of Cedar Point at Iron City, is also probably of Upper 

 Richmond age. While these rocks suggest deposition in shallow 

 waters, and the probable vicinity of shore lines, their relation to 

 a probable mass of elevated land toward the westward is unknown. 

 The relation of this problematical mass of elevated land to the 

 Nashville dome, as the southern half of the Cincinnati geanti- 

 cline is sometimes called, also remains in doubt. 



16. As determined by observations in Ohio, Indiana, and Ke?itucky. 

 — In Ohio, Indiana, and Kentucky no unconformity has been 

 noticed between any of the subdivisions of the Niagaran. The 

 Cayugan is represented by a series of strata not sufficiently 

 studied as yet to be divided into horizons. The Sali?ia division 

 is represented by the Eurypterus bearing beds at Kokomo, 

 Indiana. In New York and adjacent Ontario these beds have 

 been called the Bertie or Lower Waterlirne. The Ma?dius division 

 of the Cayugan is represented in part by the hydraulic limestone 

 at Belleville, Sandusky count3^ Ohio, and the Greenfield lime- 

 stone in the southern part of the state, as far as may be deter- 

 mined by the presence of OrtJiothetes i?iterstriatiis [0. hydrau/iais) , 

 a fossil characteristic of the lowest or Cobleskill subdivision of 

 the Manlius in New York, Pennsylvania, and Maryland. Spirifer 

 vanuxemi, found on Put-in-Bay Island, Lake Erie, and Lcpcrditia 

 alta, identified at Bellevue, Sandusky county, Ohio, are charac- 

 teristic of the Manlius proper, the upper member of the Manlius 



