1855.] 441 



not be adult and its sex is not stated. It does not appear to be related to Stri- 

 giceps, Lesson. 



This species will be carefully figured in the Atlas to my volume on the Quad- 

 rupeds and Birds of the Exploring Expedition now nearly ready. 



Note on the Miocene and Post-Pliocene deposits of California, with descriptions of 



two new Fossil Corals. 



By T. A. Conrad. 



Post-Pliocene deposits of shells occur at various places on the coast of Cali- 

 fornia, as Santa Barbara, San Pedro, <fcc, but I have seen specimens of Miocene 

 fossils from no other locality on the coast than near the former town, where they 

 were obtained by Dr. Heermann, who informs me that they are very little elevated 

 above the sea, and that the Post-Pliocene fossils rest immediately upon them. 

 This Miocene deposit consists chiefly of fine loose brown sand and small corals, 

 the most of which are a species herein described as Idmonea Californica. The 

 shells have been described in the Proceedings for February, 1855, p. 267, and 

 consist of Mercenaria perlaminosa, Pecten Heermanni, Diadora crucibuliformis, 

 Pandora bilirata and Cardita occidentalis. 



The Mercenaria and Pecten are closely related to species of the "Virginia 

 Miocene, and indeed there is an extraordinary analogy in all the above mentioned 

 shells to species of the Atlantic Miocene deposits ; and what is equally remark- 

 able, they have no resemblance to the existing California species, many of which 

 are imbedded in sand above them; affording perhaps a stronger contrast between 

 the two groups than occurs in any other part of the world. The Atlantic 

 Miocene and Post-Pliocene on the contrary contain a few species in common and 

 others which are analogous. 



'O' 



IDMOXEA, Lamourouz. 



Idmonea Californica. Branches compressed, slender, bifurcated ; tubular open- 

 ings projecting, irregularly grouped, but disposed to form in transverse series ; 

 longitudinal line between the openings or cells, microscopic or obsolete ; reverse 

 surface plano-convex, tranversely wrinkled and slightly furrowed ; section exhi- 

 biting 15 to 20 angular pores. 



The branches of this species are about of an inch wide. I havo not seen 

 any among them anastomosed. It belongs to the genus Crisisina, D'Orbigny. 



Among these corallines, is a species of Tubulipora, a Retepora and a Lichenopora 

 which may be named 



Lichmopora Californica. Adhering ; tubular openings numerous, arranged in 

 irregular branching rays ; central depression rather deep and with numerous 

 unequal pores. Diameter about of an inch. 



Post-Pliocene. 



Near Santa Barbara and San Pedro, Dr. Heermann collected a number of fossil 

 shells of the same species which inhabit the adjacent coast, among which are 

 Platyodon cancellatum, Conrad, Schizothcerus JVuttallii, Con., Vinus Nuttallii, Con., 

 Tellina nasuta and Tapes diversa, Sowerby, among the bivalves, and a number of 

 univalves. 



.Description of a new species of Pentamerus. 

 By T. A. Conrad. 



Pentamerus laqueatus. Ovate ; larger valve inflated, with about 28 angular ribs ; 

 mesial ridge but little prominent, with 56 ribs rather larger than the others ; 

 smaller valve slightly ventricose with a wide but shallow depression on each 

 side ; basal margin sinuou3. 



Locality. Delphi, Indiana. Mr. Hill. This species resembles P. Aylesfordii, 

 but is quite distinct. 



