238 University of California Publications in Geology [Vol. 9 



Near the middle of the beach section, one-half mile north of the 

 mouth of Guthrie Creek, several very good fossil localities are 

 to be found. From this horizon as many as thirty species, prin- 

 cipally small gasteropods, were obtained. The bluffs opposite Rio 

 Dell contain the most abundant fauna of any locality that the 

 writer has so far encountered. Some of the strata, a foot or 

 more in thickness, are composed almost entirely of fossil inverte- 

 brates. Over fifty pounds of perfect specimens were collected 

 in a part of one day from the central part of the section one mile 

 north of Scotia. 



One of the most noticeable characters of the fauna from the 

 Wildcat Series is the division which can be made between the 

 upper and lower portions, which agrees very closely with the 

 lithologic divisions. The lower portion contains some species which 

 are common to the Empire Formation of Coos Bay and other Mio- 

 cene formations along the coast of California and Oregon. The 

 upper portion contains a fauna quite similar to that of the Merced 

 Series, and is very conspicuously boreal in character. The upper 

 part of the lower division contains Pecten dilleri Dall, Argobuc- 

 cinum arnoldi Martin, Chrysodomus lawsoni Martin, and numerous 

 other species which are not found in the beds above. On the other 

 hand, the upper division contains a large number of species which 

 do not occur below. There is a distinct break in the fauna corre- 

 sponding to the two lithologic divisions. If this series were to be 

 divided between the Miocene and the Pliocene the separation would 

 probably come between the two divisions that are indicated by the 

 lithology and the fauna. 



The following species were obtained by the writer from the 

 lower division of the Wildcat Series : 



Pelecypoda 



Glycimeris, sp. 

 Macoma calcarea Gmelin. 

 Macoma nasuta Conrad 

 Pecten dilleri Dall 

 Pecten propatulus Conrad 

 Solemya ventricosa Conrad 

 Thyasira barbarensis Dall 

 Thyasira bisecta Conrad 

 Yoldia striagata Dall 



Gasteropoda 



Argobuccinum arnoldi Martin 

 Argobuccinum scotiaensis Martin 

 Chrysodomus andersoni Martin 

 Chrysodomus lawsoni Martin 

 Chrysodomus scotiaensis Martin 

 Chrysodomus eurekaensis Martin 

 Liomesus sulculatus Dall 

 Margarita condoni Dall 

 Solariella peromabilis Carpenter 

 Turris perversa Gabb 

 Turris cammani Dall 



The following list of species were obtained from the upper 

 division of the Wildcat Series : 



