distinction between these two; point out Elizs material and Mobridge forms, indicate distinct nicolleti types low in Pierre. Question is are there 2 distinct forms or do they merge. Necessitates study of D. nicolleti - thorough strat. and zoogeog. one. 6 D. roznensis: JAJ has one from Mobridge equivalent in Canada. This specimen a fragment of fairly stout though compressed form with course ribs. Num. of spcs. is 15 Nodes - ventro-lat. nodes on all but 3 cyclo. ribs which are limited to v.l. periphery. two lateral rows which die out forward and umbilical bullae which increase forward. If this is roznensis, question of distribution in interior. Not reported (yet) from U.S. Mobridge. In Trail City it comes in at Limopsis conc. horizon. Several possibilities; either this not 3