1916] 



Dickerson: Tejon Eocene of California 



475 



Heilprin 88 was the next writer to point out faxmal similarities. He 

 compared Cardita planicosta Gabb with the typical V. planicosta and 

 agreed with Gabb that there was a difference in the shape of the ribs. 

 "Dosinia elevata Gabb appears to be very closely allied to the Dosi- 

 niopsis meeki of Conrad of the lower Eocene of Maryland and Vir- 

 ginia." "Meretrix hornii, a form allied to, but not as produced 

 posteriorly as the Cytherea suberycinoides of the Paris basins." 

 Tritonium paucivaricatuni is, according to Heilprin, a Cancellaria 

 which is "a form so closely related to C. evulsa of Brander from the 

 British Bartonian (upper Eocene), that it may well be doubted that 

 it is at all specifically distinct". Megistostoma striata, according to 

 Heilprin, exhibits no characters which will distinguish it from Bul- 

 laea expansa Dixon of the Eocene of Brackelsham, England, and the 

 Paris Basin. 



Harris 89 was the next investigator to compare representative spe- 

 cies of the West Coast and the East Coast Eocene. He says : 



While comparing the Texas Eocene fossils with type specimens and 

 others in the collection of the U. S. National Museum and in the Phila- 

 delphia Academy of Natural Sciences, I have been impressed with the 

 remarkable sameness in the faunal characters throughout the vast extent 

 of the lower Claiborne or Lisbon horizon; many of the species from South 

 Carolina are identical with those from the banks of the Rio Grande, and 

 the rocks from Fort Tejon, California, furnish a very similar fauna 

 with several identical and many analogous species. Gabb's Cardita hornii 

 is Venericardia planicosta Lam., as held by Conrad; the type specimen is 

 slightly malformed and imperfect but others from the same locality are 

 quite typical V. planicosta. Gabb's Architectonica cognata is Conrad's 

 Solarium alveatum ; Gabb's Architectonica hornii, Conrad's Solarium 

 amoenium; Gabb's Never ita secta, Conrad's Natica aetites, and so on. 

 Gabb's peculiar and characteristic little Whitneya ficus is known from 

 Alum Creek Bluff, Colorado River, Bastrop County, Texas and is in itself 

 a strong argument for the synchrony of the Texas and California beds 

 from which it is derived. Moreover in deposits of this horizon on both 

 sides of the Rockies there are similar developments in the genera Cras- 

 satella, Cytherea, Pyrula, Levifusus, Rimella, and others. 



With the above facts in mind I can not help suggesting that those 

 who have an opportunity to study the Eocene series of California (Tejon 

 deposits) would do well to look for the Midway stage which ranks 

 second in persistency among the subdivisions of the Eocene along the 

 Gulf Slope. In other words, search should be made along the Chico- 

 Tejon contact for such species as Enclimatoceras ulricii, Cucullaea macro- 

 donta, Ostrea pulaskensis, together with varieties of Venericardia plani- 

 costa, Turritella mortoni, T. humerosa and other Midway forms. 



ss Heilprin, A., Proc. Acad. Nat. Sci. Philadelphia, vol. 34, pp. 196-214, 

 1882. 



so Harris, Correlation of the Tejon with Eocene Stages of the Gulf 

 Slope, Science, vol. 22, p. 97, Aug. 18, 1893. 



