478 University of California Publications in Geology [Vol. 9 



planicosta, form y Harris of the upper Lignitic or lower Claiborne 

 stage both as regards growth stages and the mature forms. 



Generic Comparison op Midway and Te.jon Faunas 



Harris lists the following genera from the Midway stage of the 

 Gulf Eocene : 92 



Verticordia 



Pholadomya ... 



Dentalium 



Cadulus 



Tornatellaea ... 



Atys 



Cylichna 



Pleurotomella 



Surcula 



Pleurotoma 



Olivella 



Midway Genera 

 Ostrea 



Mar. 



X 



Tej. 



X 



Midway Geneka 

 Caricella 



Mar 



Tej 



X 



Plicatula 



x 



Scaphella 





Pecten 



X 



X 



Voluta 





X 



Avicula 



X 



X 



Volutilithes 





X 



Perna 



X 





Lyria 





Modiolus 



X 



X 



Mitra 





X 



Lithodomus 







Fusus 





Area 



X 



X 



Strepsidura 



X 



x 



Cucullaea 



X 



X 



Exilia 





X 



Glycimeris 



X 



X 



Pyropsis 







Nucula 





X 



Leucozonia 







Acila 



X 



X 



Mazzalina 







Leda 



X 



X 



Levifusus 







Venericardia 



X 



X 



Fulgur-Perissolax 



X 



X 



Astarte 



X 



X 



Pseudoliva 





X 



Crassatellites 



X 



X 



Trophon 



X 



X 



Protocardia 



X 



X 



Murex 





X 

 X 



Chama 







Triton 



X 



Isocardia 





X 



Pyrula (=Ficopsis) . 



X 



X 



Meretrix 



X 



X 



Calyptraphorus , 





Tellina 



X 



X 



Aporrhais 



X 





Corbula 



X 



X 



Cerithium 



X? 



X 



Lucina 



X 



X 



Turritella 



X 



X 



Gastrochaena 







Mesalia 







Martesia 





X 



Solarium 



X 



X 



Rissoina 



Keilostoma 



Calyptraea 



Xenophora 



Natica 



Amauropsis 



Scala 



Solariella 



Pleurotomaria( ?) 



Fissurella 



Enelimatoceras .... 



Of these genera listed, Enelimatoceras is the one which disap- 

 peared at the end of Midway and also at the end of Martinez time. 



92 Harris, G. D., Bulletin of American Palaeontology, vol. I, pp. 118-270, 

 1895-6. 



