132 proceedi^'gs of the paleoxtological society 



Session' op Saturday, December 30 



At 9.30 Saturday morning the Society met in general session, witli 

 President Matthew in the chair. The first paper of the program was 

 illustrated by the recently completed geologic map of the Franklin 

 quadrangle in central Tennessee and by lantern slides. 



EMBAYMEXTf< AXD OVERLAPS IX CENTRAL TEXXESSEE 

 BY R. S. BASSLER 



{Abstract) 



On account of incomplete knowledge, paleogeographic maps can seldom be 

 made with great accuracy'. By a combination of the Columbia folio map of 

 Hayes and Ulrich and the geological map of the adjoining Franklin quadrangle, 

 just completed by the writer, the geology of a considerable area in central Ten- 

 nessee is now available in much detail and the distribution of the formations 

 can be plotted in the form of paleogeographic maps. Such maps show that 

 certain formations, as the Richmond, Brassfield, and New Providence, occupy 

 embayments in the old Nashville dome, while the Lowville, Leipers, Bigby, 

 Cannon, and other formations show broad overlaps generally to the east or to 

 the west, caused probably by oscillation of the area. 



Convincing data as to the Richmond age of the Arnheim formation of 

 the Ohio Valley, hitherto believed by some to belong to the Maysville 

 group of the Ordovician, were presented in the following paper, which 

 was discussed by various members of the Society: 



THE BASAL RICHMOXD OF THE CINCIXXATI PROYIXCE 

 BY W. H, SHIDELER 



(Abstract) 



The top of the Maysville (Mount Auburn) is everywhere, in Ohio, Indiana, 

 and Kentucky, separated from the base of the Richmond (Arnheim) by evi- 

 dences of a stratigraphic break. This appears to be due merely to a cessation 

 of deposition, as there is nowhere in the Cincinnati province anj- evidence of 

 post-Maysville and pre-Richmond erosion. 



In Ohio and Indiana the fauna of the lower or Sunset subdivision of the 

 Arnheim seems, on superficial examination, to consist of a distinct Maysville 

 element (largely recurrent Corryville), plus a Richmond element. Upon close 

 examination the recurrent Corryville forms are found to be mostly undescribed 

 species. The Richmond element appears, not at the Dinorthis carlcyi zone in 

 the middle, but at the base. Here it appears everywhere except in the more 

 southern exposures in Kentucky, where the strata are largely barren of fossils. 



President Matthew then presented for the author an abstract of three 

 papers dealing with pro! )1 ems in vertel)rate paleontolog}^, as follows: 



