36 — 



PAET V. 



DESCRIPTIONS AND FIGURES OF NEW SPECIES OF CRETA- 

 CEOUS AND CRETACEOUS B (OR EOCENE) FOSSILS OF 

 CALIFORNIA, WITH NOTES ON TERTIARY SPECIES. 



With six plates, and a Catalogue of San Diego County Cretaceous 

 and Cretaceous B or Eocene Species. 



I. CRETACEOUS AND CRETACEOUS B OR EOCENE. 

 REMARKS ON THE FOSSILS COLLECTED BY W. L. WATTS. 



The first group of species here described and figured belongs to the 

 division named by Professor Gabb, " Cretaceous B," which has been 

 generally considered by other authorities as representing or including 

 all of the " Eocene " yet discovered along the West Coast. There is, 

 indeed, no constant line of division either in the stratigraphy or the 

 palaeontology, by which Div. B can be constantly separated from the 

 undoubted Cretaceous strata beneath it, unless we make an arbitrary 

 rule excluding from the Cretaceous all strata in which no Ammonitidse 

 are found. There we find the difficulty confronting us that a large 

 number of species of other families of shells seem to be identical on 

 both sides of this line of division. It is, however, possible that com- 

 parison of better specimens may yet prove some of these species to be 

 different, and that others have been accidentally buried in the newer 

 strata by being washed out of the older ones where before imbedded. 

 It is certain at least that the two localities from which Mr. W. L. Watts 

 obtained the specimens described, furnish no Ammonitidae, but this 

 may be explained on the theory that they represent shallow water 

 deposits close to a seashore or estuary, in which large quantities of 

 vegetable matter from the land were accumulated. Both the probable 

 habits of the species found at the coal mines near Huron, Fresno 

 County (as compared with nearly related species), and the presence of 

 coal in the rocks containing them, point to such a conclusion, and the 

 occurrence of many of the same species, together with a thin bed of 

 coal somewhat farther away, indicate that the species from Marysville 

 Buttes inhabited a similar but somewhat deeper sea. There is much 

 reason to believe that it was a deep inlet like the Gulf of California, or 

 perhaps a more open channel connected with others running among 

 islands which formed the commencement of the present Coast Range. 



