182 University of California Publications in Geology [Vol. 11 



PSEUDOPERISSOLAX?, sp. indt. 



Several imperfect specimens of a species, which appears to belong 

 to the genus Pseudoperissolax, were found near the upper part of 

 the San Lorenzo beds on the north side of Mount Diablo at University 

 of California localities 2038 and 3081. All the specimens at hand are 

 casts ; good material, showing the upper whorls of the spire and 

 aperture, was not obtained. The body whorl is biangulate, with a 

 fairly broad, slightly upward sloping tabulation between the suture 

 and the upper angulation; about twelve rather sharp nodes on each 

 angulation; these, on some specimens, merge into faint longitudinal 

 ribs extending from the suture to the lower angulation; only one 

 of the angulations shows on the whorls of the spire. Surface also 

 sculptured by fairly coarse spiral ribbing; every alternate spiral rib 

 is heavier than the one in between. Interspaces slightly wider than 

 the narrower ribbing on body whorl ; three or four spiral ribs between 

 the upper angulation and the suture ; seven or eight between the 

 angulations. Canal straight, fairly long. 



Genus AGASOMA Gabb 



AGASOMA ACUMINATUM Anderson and Martin 

 Plate 22, figures 11 and 19 



Agasoma acuminatum Anderson and Martin, Proc. Calif. Aead. Sei., ser. 4, 



vol. 4, p. 73, pi. 5, figs. 4a, 4b, 1914. 

 Agasoma acuminatum Anderson and Martin, Clark, Univ. Calif. Publ., Bull. 



Dept. Geol., vol. 9, no. 2, p. 15, 1915. 



This species appears to be one of the most important markers of 

 the Oligoeene of the West Coast. It is found in the Sooke beds of 

 Vancouver Island and is also common in Oregon, the type coming 

 from about ten miles northwest of Scappoose, Oregon. 



AGASOMA GRAVIDUM Gabb 

 Plate 19, figures 1, 3 and 5 

 Clavella gravida Gabb, Geol. Surv. Calif., Palaeontology, vol. 2, p. 4, 1866. 

 Agasoma gravida Gabb, Geol. Surv. Calif., Palaeontology, vol. 2, p. 46, 

 pi. 1, fig. 6, 1869. 



Agasoma gravida Gabb, Merriam, Univ. Calif. Publ., Bull. Dept. Geol., 



vol. 3, no. 16, pp. 378, 380, 381, 1904. 

 Agasoma gravidum Gabb, Smith, Proc. Calif. Acad. Sci., ser. 4, vol. 3, 



pp. 165, 175, 178, 1912. 

 Clavella gravida Gabb(?), Dall, 17th Ann. Rep. U. S. Geol. Surv., pt. 1, 



p. 467, 1895. 



