Vol. 4] Weaver. — Palaeontology of the Martinez Group. 103 



division, designating them as .1 and B and including in the 

 former all the beds now known as Chieo, Horsetown and Knox- 

 ville. His upper division, Cretaceous B, comprised the upper 

 division of the Eocene as known to-day. Later, in 1869, when the 

 second volume of the Palaeontology appeared, this classification 

 was more clearly defined. Cretaceous A was subdivided into the 

 Shasta and Chieo groups, and division B was named Tejon. 

 Between the Chieo and Tejon he provisionally placed the Mar- 

 tinez Croup, which he considered to be of small geographical 

 extent, and suggested that it might be a subdivision of the Chieo. 



The list of fossils collected from the Martinez beds by Gabb 

 appeared to indicate a possible transition from the Chieo to 

 Tejon, and when later the Tejon came to be regarded as Eocene, 

 still more significance was attached to these "Intermediate beds." 



The classification as set forth in the Palaeontology of the Cali- 

 fornia Survey conflicted with later views, and hence led to 

 confusion. This confusion was largely cleared up in a paper 

 on the "Cretaceous and Eocene of the Pacific Coast" by Dr. 

 T. W. Stanton,* in which he reorganized the earlier classification, 

 basing it upon the results of more detailed investigations. In 

 this new arrangement he divided the Martinez Group of Gabb 

 into two parts and, on the basis of its faunal and stratigraphic 

 relations, placed one part in the Chieo and the other in the 

 Eocene, designating the latter as lower Tejon. 



In the following year a discussion of the question was 

 published by Professor J. C. Merriam.f This investigation 

 was based on a study of the geological relations of the Martinez 

 Group at the typical locality. An extensive collection of fossils 

 was made, extending into both the Chieo below and the Tejon 

 above. From the data obtained he was able to show that the 

 Martinez fauna, consisting of over sixty species, was a unit quite 

 distinct from the Chieo and Tejon. Only a very few species 

 were found in common with them. On a lithological basis he 

 distinguished the Martinez from the adjoining formations, in 

 that it showed the presence of considerable quantities of glau- 



*The Faunal Relations of the Eocene and Upper Cretaceous on the Pa- 

 cific Coast. 17th Ann. Rep. IT. S. Geol. Surv., pp. 1011-1060, 1895-96. 



tThe Geologic Relations of the Martinez Group of California at the 

 Typical Locality. Jour, of Geol., Vol. 5, pp. 767-775, 1897. 



