102 



University of California Publications in Geology 



[Vol. 8 



genera. The beds in which the fossils occur are of Eocene age and 

 of the Martinez stage. They possibly represent a lower phase than 

 has been recognized in the type locality of the Martinez or in the 

 region north of Mount Diablo. 



Fossils had previously been found in the same formation at Mon- 

 tara Mountain by Merriam and Ransome, and a brief note concerning 

 their occurrence was given by Lawson 20 in "A Sketch of the Geology 

 of the San Francisco Peninsula ' ' : 



On the northeast slope of Montara Mountain, on the crest of Whiting 

 Ridge, a number of imperfect fossils were found. . . . The matrix in which 

 they occur is sandstone. These fossils were submitted to Mr. Stanton, who 

 kindly prepared the following statement concerning them: "The fossils are 

 nearly all casts of small Lamellibranchia, usually showing some of the features 

 of the external surface and so few of their characteristics that most of 

 them can not be determined even generically. Several specimens, however, 

 that retain impressions of the hinge, belong to the Arcidae, and some of these 

 seem referable to Pectunculus, a genus that ranges from Lower Cretaceous to 

 the present time. One small imperfect cast has the form of Opis, and if we 

 could be certain that it is that genus it would fix the age as Mesozoic, with 

 the probabilities in favor of Lower Cretaceous or Jurassic. On the other hand 

 there is a fragment showing the imprint of a small part of the surface of a 

 shell that, in the ornamentation, is very much like some of the late Tertiary 

 and recent species of Venus. These notes are sufficient to show that there are 

 no characteristic forms recognizable in the collection that are decisive of its 

 Mesozoic or Cenozoic Age. There is nothing among them that suggests the 

 Palaeozoic. It is hoped that these beds may yield to future search some better 

 preserved forms which will decide their age." 



Professor Lawson informs me that these beds are directly con- 

 nected with those of San Pedro Point, so that they too are to be 

 regarded as Martinez Eocene. 



EOCENE (?) OF THE SANTA CRUZ QUADRANGLE 



The fauna from this locality which was listed above in the review 

 of the literature was, at the time of its discovery, so unique that its 

 stratigraphic position was questioned. Terebratulina tejonensis Stan- 

 ton was the only previously described species listed in the entire fauna. 

 The species which was identified as Terebratulina tejonensis by Arnold 

 differs slightly from T. tejonensis. It is broader in outline and the 

 ribs are more numerous. A cidarid spine is found in the basal Mar- 

 tinez which resembles Cidaris merriami Arnold, but it has only ten 



26 Lawson, A. O, op. cit., p. 445, 1894. 



