420 A. HYATT TRIAS AND JURA IN THE WESTERN STATES. 



Cardinia gibhosum (?). 



Unlcardium (?) glbbosuni, Meek. Pal. Cal., vol. i, pi. 8, fig. 8. 



Loc, Beaver creek. 



This shell has the general form and aspect of a shell of this genus, and 

 is a close ally with a similar shell of the Mormon sandstone at Taylor- 

 ville. The surface is evenly covered with rather fine concentric ridges, 

 and the beaks are very prominent and larger, and the outline differs 

 from Taylorville species. It may have been, when undisturbed by com- 

 pression, identical with Meek's figure as quoted above. 



Rhynchonella, sp. (?) 

 Loc, Beaver creek. 



This shell does not closely resemble Rhynchonella myrina of the Hard- 

 grave sandstone, nor any species of this genus occurring in' that region. 

 It approximates in outline to the R. gnathophora in part, as figured by 

 Meek,* but differs in having three prominent, sharp costse on the elevated 

 central area of the pedicle valve and only five costse on either side. 



UPPER JURA FOSSILS OF THE GOLD BELT SLATES. 

 AMMONITIN.E. 



■^[,^^ y'Cardioceras dubium, n. s. 



Loc, Texas ranch, Calaveras county, California. 



The 3^oung are imperfect, but it can be readily seen that the earliest 

 stages were smooth for a prolonged period, as in some species of the genus 

 Cardloceras, and that they differ entirely from the heavily tuberculated 

 young of the genus Amnltheas. 



The costse arise rapidly and do not appear to differ materially, so far 

 as seen on the sides, from those of later stages. This is also more con- 

 sistent with the characteristics of Cardioceras than with those of Amal- 

 theus. 



The costse on the sides and genicular ridges are numerous, linear and 

 single. There are no lateral tubercules, but occasionally the costse dis- 

 appear on the sides just before reaching the geniculse. The geniculae are 

 very prominent and tuberculated. 



The whorls are compressed, with sides flattened. The venter is very 

 narrow. The inclusion varies from about one-third the diameter of the 

 inner to considerably less, and there may be two species, one including 

 more involute and the other the less involute forms, but both have what 



* I'aleontology of California, pi. 8, fig. 1 and la. 



