6 CALTFiil.'MA ACADKMY dl' SCIK.N'CKS 



Sprciiiicus wrrc found at miiiicnius lucalitics in the cxtctisivc outci-oiis of this 

 linicstoni', hut the pi'inciiial concctioiis were UKuh' at localities known as Smith's 

 ( 'ovc. Hear Cove, Grassy I'oint anil North Fork. The lii'st three localities are 

 all on I-Jroek Mountain, at tlie southern end of the belt of limestone nortli of the 

 l*itt. Smith's Cove' lies on the soutliwestern side of the ridge. Grassy I'oint' on 

 the northwestern side, and Fx'ar Cove'' near the middle of the eastern side. 

 North Kork^ is a locality on the north foi-k of S([uaw Ci'eek and ahout two miles 

 northwest of the Kelley Kancdi. 



The l)ones occur in practically all horizons of the limestone, hut good 

 material is more common, or at least more easily obtaineil, in the softer, slightly 

 shah' hiN'crs widl e.xjiosed at the localities mentioned. 



The limestone section has heen divided hy Professor James. Perrin Smith ■\ 

 on the basis of faunal distribution, into the upper or Spiriferina beds, middle or 

 Juvavites beds and lower or Tratdiyceras Ijeds. The softer layers, where the best 

 specimens were obtaine(l, Ixdong in general to the lowei' oi" Trachyceras horizon. 

 In the other beds the material seems to be much more fragmentary and little 

 but loose bones or teeth was ol)tained. 



in all eases the remains have been very tirndy united with the black 

 limestone matrix, and successful preparation was possible only with the aid of 

 an electric engine. As the bones are black, as well as the matrix, it was in 

 manv cases impossible to trace their outlines until they had been moistened with 

 hv<lrochloric acid and allowed to stand for some days. This treatment resulteil 

 in the appearance of a (hdicate blue tint in the bone, evidently due to the 

 pi'esence of the ndneral \'i\'ianite. making it possible to follow the lines of con- 

 tact with little difhculty. 



.\ssociated with the thalattosaurian remains are numerous ichthyosaurian 

 bont's, a few selachian teeth, occasional ganoid scales, and great nund)ers of 

 molluscan slndls. There are also a few brachiopods, corals and echinoids. The 

 most c(nnmon of all forms are (he ce])halopods. which fre(|uently make up a 

 large pai't of the rock. In the moi'e shaly layers they may be replaced by the 

 lanudlibrantdi genus llahihin. \ list of the most characteristic genera would 

 incdude the following: vert(d)rates, — Shasfasaurus, Delphivosanrns, Tdrddoieniiix, 

 Merridniid, Ihjhdihix: in\'ertebrates, — Tropitcs, Sdfjeiiifcs. Kntdiiidccrdx, .hwdrifi's, 

 I'olycyrhi.'i. I'minicln/ccrds. Tirdlitcs, ArpadH('>^. Arcixlrx. Ortlmfcrds. Xunfihi.-!. Atrdctifcs, 

 Halobia, Rhynchonella, h^piriferina, Ciclarls. 



1 Sec. 11 and 12, T. U N. It. 2 W, Mt. D. Mcrid. 



2 Sw. 3."), T. 35 N, R. 2 W, Mt. 11. Mfrici. 



3 Sec. :«, T. 3.5 N, R. 2 \V, Mt. I). Meriil. 



4 Sec. 1, T. 3.T X. ami Sec. 3li, T. 'X, N', U. 2 \V, .Ml. I). Mciiil. 



5 See Comparative Slratigraiihy of the Marine Trias of Western .\nieriea, I'roe. Calif, .\eail. Sei. M ser. lieoi, v. 1, no, 111, 

 [>. 300. 



