FOSSIL SHELLS IN THE RANGE. . T8 



fossils included belong to the upper Miocene group, corresponding to the "Faluns" of M. 

 Cordier, which from its great thickness forms one of the most remarkable features in the geology 

 of California. The soil, formed by the debris of the strata, varies with the nature of the stratum 

 decomposed. The green sandstones are calcareous, and form a fertile soil, while the brown and 

 yellow sandstones form only a barren sand by disintegration. 



In the strata on the north side of the mountains (in Santa Inez valley) the following fossils 

 were obtained, (for the description of the species vide Palfeontological Eeport.) 



In the lowest stratum, (nearest camp,) bed 2 : 



Mytilus Inezensis, Turritdla Variata, 



P^achydesma Inezana, 

 constituted the only species, but existing in remarkable abundance, in some layers pachy- 

 desma predominating, in others turritella. 



In the sandstones which lay above this bed, which were of a light yellow tint, bed 3, were : 



Tayelus, {CuUeUus, Conrad,) Tapes Inezensis, 



Turritella Variata, Crassatdla collina, 



Cydas permacra, 

 along with comminuted portions of an Ostrea. 

 In the upper bed, bed 4, were found : 



Turritella Inezana, Cydas Estrellana, 



Natica Inezana, Cydas permacra, 



Peden Magnolia, Peden (perhaps young magnolia.) 



Balanus Estrellanus, 

 In the strata on the south side were observed, in the Gaviote pass : 



Crassalella collina, Turritdla variata, 



Ostrea Panzana, Pachydesma Inezana, 



Mactra Gaviotensis, Tapes Montana. 



Mytilus Inezensis, 

 Among the foot hills, near Santa Barbara, (Camp 25:) 



Peden Meelcii, Cydas Estrellana, 



Natica Inezana, Pecten discus, 



Balanus Estrellanus, 

 and southeast of the town of Santa Barbara the foot hills contain a layer of Ostrea Panzana. 



It is highly probable that the brown and yellow sandstones of the Gaviote are the middle beds, 

 and lie between beds 1 and 2 of those on the north side ; they possess Turritella and Pachydesma 

 in common with the northern beds, and have the ostrea layers extensively developed. The beds 

 at Camp 25 are the representatives of bed 4 of the north side, but possessing the Pecten Meekii, 

 a fossil also present in the foot hills of San Rafael sierra, where it is accompanied by Balanus E., 

 rendering it exceedingly probable that the strata of San Rafael are similar to those of Santa Inez. 



The upper beds on the north side, as well as the upper beds on the south side, are distinguished 

 by the abundance oij^^den, it being the dominant shell. 



Mytilus and Pachydesma dominate in the lower beds of the north side, while they are sparing 



fossils of the Gaviote, where ostrea is the dominant shell. The numbers of species common to 



this sierra and the slopes of the San Jose mountains, at Panza, show that similar conditions 



existed 100 miles further inland, as at Santa Inez, yet the absence of Asterodapsis, Pallium, 



10 U 



