PLATE IV. 



Fig. 1. Platystrophia colbicnsis-prcciirsor. Brachial valve. At mile post 627, 

 between Colby and Winchester, Kentucky, in the Greendale divi- 

 sion of the Cynthiana formation. 



Fig. 2. Platystrophia colbieusis. A, brachial valve; B, pedicel valve. Along 

 the railroad, a mile and a half southwest of Carlisle, Kentucky, in 

 the Greendale division of the Cynthiana formation. 



Fig. 3. Platystrophia colbiensis-mutata. Brachial valves. Five miles west 

 of Winchester, Kentucky, along the railroad to Colby, in the Green- 

 dale division of the Cynthiana formation. 



Fig. 4. Platystrophia profitndosulcata-hopensis. Brachial valve. Cincinnati, 

 Ohio, in the Mount Hope bed. 



Fig. 5. Platystrophia crassa, James. A, cardinal view; B, brachial valve. 

 Cincinnati, Ohio, near the middle of the Fairmount bed. 



Fig. 6. Platystrophia unicostata, Cumings. Brachial valve. Above the con- 

 spicuous Platystrophia poudcrosa horizon in the Bellevue bed, near 

 foot of road from New Hope church to Willard branch of the 

 south fork of Laughery creek, in Ohio county, Indiana. 



Fig. 7. Platystrophia cypha-conradi. Brachial valves. Along the Bardstown 

 pike, half a mile south of Smithville, in Bullitt county, Kentucky, 

 in the Arnheim bed. 



Fig. 8. Platystrophia acutilirata-inflata, James. A, cardinal view; B, brachial 

 valve. Types, No. 1561, from the Walker Museum of Chicago 

 University. This form occurs in the upper part of the Whitewater 

 beds at Richmond, Indiana. James collection. 



Fig. 9. Platystrophia acutilirata, Conrad. Brachial valve. 



Fig. 10. Platystrophia cypha, James. A, brachial valve; B, anterior view. 

 Warren county, Ohio. Type, No. 2326, from the Walker Mu- 

 seum at Chicago University. James collection. 



Fig. 11. Platystrophia cypha-versaillesensis. Brachial valves. Versailles, In- 

 diana, from the Liberty bed. 



Fig. 12. Platystrophia cypha, James. Mount Sterling, Indiana, from the Belle- 

 vue horizon, immediately over the conspicuous Platystrophia pon- 

 derosa horizon. 



Fig. 13. Platystrophia cypha-versaillesensis. Intermediate between the forms 

 conradi and versaillescnsis. North of Hogan creek, on the road 

 from Moores Hill to Holman, Indiana, about 25 feet below the 

 Hebertella iiisculpta horizon, in the Blanchester division of the 

 Waynesville bed, associated with an abundance of Lepfaen'a rich- 

 mondcnsis. 



Fig. 14. Platystrophia cypha-conradi. Half a mile south of Smithville, Ken- 

 tucky, in the Arnheim bed. Brachial valves. 



