180 PAL^OXTOLOGY. 



Length, about 0.95 inch ; breadth, 0.60 inch ; length of aperture, 0.45 

 inch ; breadth of aperture, 0.30 inch. 



I have been incHned to refer this shell to C. paludin(Bformis (z^Turho 

 pahtdinreformis, Hall), figured in Fremont's Report; but the fact that that spe- 

 cies is said to be associated with Goniobasis nodulosa (rz CeritJiium nodulosum, 

 Hall), in a light-colored "Oolitic limestone", seems to be a very strong 

 objection to the conclusion that it can be the species here under considera- 

 tion ; the latter being from dark, carbonaceous, shaly and arenaceous beds, 

 probably belonging to a very different horizon. I have seen specimens 

 believed to belong to G. nodulosa, in a light- colored matrix from this region, 

 densely packed with Cypris, presenting much the appearance of oolitic par- 

 ticles ; but these came from an entirely different formation, containing a 

 different group of fossils from those found in the strata from which the 

 shell under consideration was obtained. In size and general appearance, 

 our shell is not very unlike Professor Hall's figures of C. paludincsformis ; 

 but still it has a less oblique suture and more convex volutions. 



The form here described agrees well with many specimens now before 

 me from the same locality and beds, which specimens I think most proba- 

 bly medium-sized examples of C. macrospira, founded on a much larger, 

 more elongated shell ; but, as they may possibly be distinct, I have merely 

 referred them provisionally to that species. In order to facilitate com- 

 parison, I give below a description of C. macrospira, from the original 

 typical specimens : 



Canipeloma {Melantho) macrospira. Meek. — Shell attaining a rather large 

 size, conoid-subovate ; spire elongate-conical ; volutions five or six, moderately 

 convex ; suture deep, rather oblique ; body- volution larger in jjroportion 

 to the others than would be formed by the regular rate of increase of those 

 above, and obliquely produced below ; aperture comparatively la,rge, ovate; 

 inner lip rather thick, arcuate, a little reflexed, but not covering the deep 

 umbilical indentation, in old shells rather distinct from the body-volution 

 all the way up ; surface only showing the usual slightly sigmoid lines of 

 growth. Length, about 1.80 inches ; breadth, 1.14 inches. 



The form here referred to C. macrospira seems to agree pretty well in 

 size and proportions with the upper three or four volutions of that shell ; 



