REPORT ON PAI^EONTOLOGICAL COLLECTIONS. 367 



inner whorl on the under side and less than one-fourth above embraced bv each suc- 

 ceeding- turn; umbilicus rather deep, and one-third wider than the outer whorl; surface 

 and aperture unknown. 



Greatest breadth, 1.19 inches; height, 0.25 inch. 



This is a fine large species that seems to be quite abundant. It is often found 

 much distorted by pressure, and in this way presents a great diversity of forms and 

 appearances. It resembles several Kuropean Eocene and other Tertiary forms: but, 

 so far as I have been able to make comparisons, it seems to be distinct from them all. 



Locality (tin I position. — Ham's Fork, in (Southwestern Wvoming: from beds now 

 (1875) known as the Green River group. 



Planoebis spectabilis, ear, Utahensis, Meek. 



Plate 5, fig. 8, a, b, c. 



aperture is proportionally narrower and more oblique. Its volutions also seem to 

 increase more rapidly in breadth. These differences are quite well enough marked 

 to distinguish it specifically, if we could be entirely sure that they are not, partly at 

 least, due to accidental distortion. The type-specimens have evidently been a little 

 depressed by accidental pressure, but still seem to have been naturally more depressed. 

 For the present, I have concluded to view this form as a variety of P. sprctuhUis. 

 Locality and position. — Same as last. 



Limn^ea vetusta, Meek. 



Plate 5, fig. 3, a, b. 

 Limncea vetusta, Meek (July, 1860), Proceed. Acad. Nat. Sci. Philad., XII, 314. 



Shell elongate-subovate; spire rather slender and pointed; volutions five and a 

 half to six, compressed or moderately convex; suture well defined: surface nearly 

 smooth, with traces of fine lines of growth, scarcely visible without the aid of a lens; 

 aperture narrow-ovate, apparently rather narrowly rounded below, and acutely angu- 

 lar above, equaling about half the entire length of the shell; columella with a small, 

 comparatively straight, fold. 



Length, 0.56 inch; breadth, 0.26 inch. 



This and the following form are more like species occurring in the White River 

 Tertiary basin than any yet known in other formations of the Northwest; but they both 

 differ from the White River species in being more slender, in consequence of the less 

 ventricose character of the body-whorl. 



Locality and position. — Same as last. 



Libouea similis, Meek. 

 Plate 5, fig. 2, a, b (mag. 2 diam.). 

 Limncea similis, Meek (1860), Proceed. Acad. Nat. Sci. Philad., XII, 314. 



This form differs from the last in having more convex whorls and a deeper, as well 

 as a more oblique suture. They may possibly be varieties of one species, but, after 

 examining a more complete series than that first studied, I am still inclined to think them 

 more probably distinct. 



Locality and position. — Same as last. 



