GASTROPODA— -MELANIIDJE. 



743 



Laramie of Colorado, Wyoming. 



461. G. invenusta M. and H. (Fig. 1078, k.) 



Smooth, with somewhat larger apical angle than preceding. 

 Laramie of Montana (upper Missouri River region). 



462. G. macilenta White. (Fig. 1078, i.) Cretacic. 

 Whorls flattened, sutures not impressed, marked by faintest of 



shelves, surface smooth. 



Bear River formation of Wyoming and Utah. 



463. G. nebrascensis M. and H. (Fig. 1078,7.) Cretacic. 



FlG. 1078. a, Goniobasis chrysallis ; b, G. chrysalloides ; c, G. cleburni ; d, G. 

 convexa ; e, f, G.endlichi; g, G. gracilenta ; h, G. invenusta ; i, G. macilenta ; j> 

 G. nebrascensis ; k, G. sub/crvis ; I, m, G . subtortuosa ; n, o, G. tenuicarinata ; p, G. 

 simpsoni ; q, G. ienera ; r-t, G. nodulifera ; u, v, G. carteri ; w, G. columinis. 

 (After Whitf., U. S. G. S., III.) 



Smooth, broad, thick, sutures slightly impressed, surfaces gently 

 convex ; lines of growth the only surface marking. 



Laramie of Yellowstone River region ; Canada, upper Missouri 

 River region ; Colorado and Utah. 



