FAUNA OF THE KNOXVILLE SERIES. 199 



Three otlier species, viz, Ammonites ramosns Meek, Potamides diadema 

 Gabb, and Lima skastacnsis Gabb, the types of which Gabb obtained in 

 the Horsetown beds, Dr. White thinks probably, but not certainly, identical 

 with specimens obtained by ray party from Knoxville. 



In addition to these published species the following have been gener- 

 ically recog'uized among the collections from Knoxville, all the specimens 

 of which are, however, too imperfect for specific determination: Ammo)iitesf, 

 Margarita ?, Deiitalinm, Area, Nucntaiia, and BJii/iiclionclIa. Besides all these 

 forms there are fragments among the collections from Knoxville which 

 indicate two or three other mollnscan species not considered in the enumer- 

 ation of the fauna of tlie Knoxville beds. The specimc^ns which have been 

 referred to as prol)ab]y representing a species of Am.monites are only a few 

 small fragments, which show only portions of the sides and [jeripher}- of 

 the shell. These seem to indicate a species related to the A. Newtierriji of 

 Meek. The Dentatitim is probably undescribed, as are ])robably also the 

 Area and Nuculana. The RliynclwneJla is apparently an undescribed species 

 and seems to be identical with one whicli Dr. Wiiite discovered at Horse- 

 town.' The collection contains only one fragment of a shell which he 

 refers witli doubt to Margarita. 



The specimens of Ammonites which in the foregoing list of published 

 species are referred with doubt to A. ramosus Meek consist only of the 

 small inner whorls, none of them reaciiing an inch in diameter. The form, 

 -surface markings, and septa of the shell, so far as these characters are shown 

 by the Knoxville specimens, seem, however, to agree well with those of the 

 species as it is described by both Meek and Gabb. Meek's type specimens 

 came from Vancouver Island, but Gabb identified the species in the Horse- 

 town beds of the Shasta group of California.- The specimens of the shell 

 which in the foregoing list are referred with doubt to the Potamides diadema 

 of Gabb are embedded in compact rock, so that all its characters cannot be 

 observed. They are probably identical with Gabb's species which he de- 

 scribes as coming from the Horsetown beds. Finally, so far as the specific 

 identity of anv Bcleninites can be determined, there seems to be compara- 



' This form is closely Itlie the R. oxtjoplicata Fischer, from the Jurassic of Moscow. 

 'See Bull. U. S. Geol. Sur. Terr. (1876) No. 2, p. a71, PI. V, Fig. 1; also, Geol. Survey California, 

 PaliPODtology, vol. 1, p. 65, PI. XI, Fig. W, aud Pi. XII, Fig. 12i. 



