DESCRIPTION OF NEW FORMS OF UPPER CAMBRIAN FOSSILS. 



liY 



Charles D. Walcott, 



Iloiiordrv Ciira/or Deparliiu7it of Paleozoic hiveiidnatf Fossils. 



(Witli Plates XX, XXI.) 



In the course of a review of the Cambrian fannas it becomes necessary 

 to designate a number of nndescribecl species by name in the lists from 

 the various localiiies. They are from New York, Wisconsin, Minnesota, 

 Texas, Nevada, and Dakota, and may all be referred to the Upper Cam- 

 brian fauna. In New York and Texas two subfaunas exist, in Wis- 

 consin three, and in Nevada two, and possibly three. 



Metoptoma? minneiskensis sp. nov. 



Plato XX, Fig. 2. 



Shell conical, broadly elli[)tical in outline, apex i)ointed, subcentral, 

 surface marked by broad undulations of growth in some specimens, 

 while in others it is nearly smooth. Peristome broadly sinuate in front 

 and back, in the narrow specimens, and usually so on the anterior side 

 in all. Outer surface of shell unknown. 



This species is one of tie numerous conical, pattelloid shells that are 

 referred to the genus Metoptoma while awaiting more definite informa- 

 tion as to theif true generic relations. Mr. W. A. Fiukelnburg sent a 

 number of specimens and Dr. Cooper Curtice collected a few. 



Formation and locality. — Upper Cambrian Sandstone (Middle horizon) 

 Minneiska, Minnesota. 



Nat. Mus. Cat., Invert. Foss., 23S44. 



Metoptoma ? peraciita .sp. uov. 

 Plato XX, Fi-. 1. 



Shell very elongate, conical, rounded, elliptical to circular in outline 

 at the aperture. Surface marked by more or less distinct undulations 

 of growth. Apex subcentral. Outer surface unknown. 



This species occurs at the same horizon as M.f minneiskensis in a fri- 

 able sandstone. It differs in being much more elongate and the less 

 excentric position of the apex. 



Proceedings National Muaeiini, Vol. XIH.— No 820. 



267 



