PEELIMINARY REPORT UPON THE INVERTEBRATE AND 

 OTHER FOSSILS: WITH DESCRIPTIONS OF NEW SPECIES 

 COLLECTED BY THE EXPEDITION FOR GEOGRAPHICAL 

 AND GEOLOGICAL EXPLORATIONS AND SURVEYS WEST 

 OF THE ONE HUNDREDTH MERIDIAN; LIEUT. GEORGE 

 M. WHEELER, CORPS OF ENGINEERS, UNITED STATES 

 ARMY, IN CHARGE. 



By C. a. White, M. D. 



LOWER SILUEIAIS^ 

 PRIMORDIAL PERIOD.*! 



PLANTS. 

 Geuus Cruziana d'Orbigny. 



Ceuztana Linnarrsoni {sji. nov.) — Body uot much flattened, oblong 

 or subelliptical in outline, but narrowed and more or less pointed at the 

 ends, one of which is more acutely pointed than the other. Median 

 furrow extending the whole length of the body, the greater part of it 

 being moderately deep and distinct ; surface showing few or no trans- 

 verse ruga3, but upon the more pointed end of some of the specimens 

 there is a secondary furrow u[)on each side of the median farrow ; these 

 extend to the point where they join the median furrow, but disappear 

 in the other direction before reaching the middle of the body. Stipe 

 rather small, attached about mid-length in the bottom of the median, 

 furrow, but it is not usually seen attached, having been lost or destroj^ed. 



Length of body, from two and a half to seven and a half centimeters. 



It is thought possible that the specimens of this species may have 

 been denuded of ragte before they became imbedded, because some of 

 the slabs upon which the specimens are found are strewn with small 

 bodies that resemble detached rugiie ; on the other hand, this seems 

 improbable, because some of these slabs are found to contain both C. 

 Linnarrsoni and the following species, the former being nude as usual, 

 and the latter having their abundant rugiB in place. 



Position and locaUtij. — Tonto Shale, Grand Canon of the Colorado 

 River, Mohave County, Arizona Territory. 



Cruziana rustica' (.s^j. nov.) — Body more or less elongated, flattened, 

 more or less distinctly bilobed, the ends being blunt ; median furrow 

 extending the whole length of the body, comparatively shallow and 

 uniform throughout. Transverse rugte numerous, distinct, extending 

 from the sides to the middle of the median furrow, and arching slightly 

 as they cross the lobes. 



* The nomenclature of the geological periods adopted in this paper is that of Dana's New 

 Manual of Geology, 1874. 



1 1 am under obligations to Professor Joseph Henry, Secretary of the Smithsonian 

 Institution, for the free use of all the lacilities possessed by it to aid me in my inves- 

 tigations. — C. A. W. 



