1922] Trask: The Briones Formation of Middle California 159 



Family Olividae 

 Genus OLIVA Brugiere 



OLIVA SIMONDSI, n. sp. 

 Plate 8, figures 5a and 5b 

 Type.— No. 12394, Univ. Calif. Mus. Pal. 



Shell medium sized, solid, coniform; spire one-third height of shell; whorls 

 five, smooth and flat; pillar with two strong plications, with a smaller one 

 between; callous extends half the distance from posterior to anterior end of 

 aperture, and extends around to the posterior canal; outer lip not preserved. 



Dimensions. — Type specimen U. C. no. 12394; alt., 36.8 mm.; greatest width, 

 23 mm.; alt. of aperture, 30.3 mm. 



Occurrence. — Briones formation, U. C. loc, no. 171. 



Named in honor of Professor F. W. Simonds, University of Texas. 



This species is very close to 0. peruviana coniformis Philippi 38 in 

 shape, but it differs from the latter in that it possesses a small plication 

 between the larger two, while in 0. peruviana coniformis the smaller 

 plication is posterior to the two larger. 



KEY TO LOCALITIES 





Millimeters 



Millimeters 







Locality 



east* 



south* 



Quadrangle 



Formation 



15 



147 



155 



Concord 



Briones 



146 



68 



264 



Mt. Diablo 



Briones 



171 



222 



29 



Concord 



Briones 



177 



208 



9 



Concord 



Briones 



409 



342 



353 



Mare Island 



Lower San Pablo 



1176 



35 



427 



Carquinez 



Briones 



1177 



27 



411 



Carquinez 



Briones 



1354 



One mile southeast of Muir 



Station. 



Concord 



Briones 



1455 



54 



256 



Mt. Diablo 



Briones 



1492 



80 



275 



Mt. Diablo 



San Pablo 



1942 



321 



193 



Concord 



San Pablo 



1949 



325 



196 



Concord 



San Pablo 



3522 



283 



210 



Concord 



Briones 



3524 



281 



223 



Concord 



Briones 



3529 



170 



223 



Pleasanton 



Briones 



3532 



78 feet south loc. 3529. 





Pleasanton 



Briones 



3534 



33 feet south loc. 3529. 





Pleasanton 



Briones 



3535 



58 feet south loc, 3529. 





Pleasanton 



Briones 



3575 



24 



225 



Mt. Diablo 



Briones 



3576 



Near San Pablo Bay. 





Mare Island 



Briones 



3581 



216 



378 



Pleasanton 



Briones 



3582 



218 



377 



Pleasanton 



Briones 



* Measurements in these two columns refer to distances in millimeters on the 

 map, east and south, respectively, from northwest corners of the topographic 

 sheets. 



38 Philippi, Abb. u. Beschr., xix, 1, figs. 5-7, 1842-1851. 



