AGE OF THE MISSOURI RIVER 25 
21. 
MacrocycUs concava. Say. 
22. 
Pupa armifcra, Say. 
23- 
P. fallax, Say. 
24. 
P. contracta, Say. 
25- 
Succinea ovalis^ GId. 
26. 
6-. f^rr////, Bid. (?). 
27. 
Bulimulus dealbatus. Say. 
28. 
Helicina orbiculata, Say. 
29. 
Pomatiopsis lapidaria, Say. 
3°- 
Tebennophorus carobuensis, Bosc. 
31- 
Limax campestris, Binn. 
32. 
Physa gyrina, Say. 
33- 
/'. hetero strophe, Say. 
34- 
LimncBa humilis, Say. 
35- 
Planorbis bicarinatus, Say. 
36. 
/'. frivolvis, Say. 
37. 
Ancylus tardus, Say. 
38. 
Melantho integra, Say. 
39- 
Pleurocera subulate, Lea. 
40. 
Goniobasis pallidula, Anth. 
41. 
Sphce.reum transversum, Say. 
42. 
Pisidium compressum (?), Prim. 
GEOLOGY. 
AGE OF THE MISSOURI RIVER. 
E. P. WEST. 
(^ Paper read before the Kansas City Institute,.^ 
Mr. President and Gentlemen : — The Missouri, one of the grandest 
rivers of the world, washes the northern limit of Kansas City. We witness its 
annual floods, garnered by the vast accumulations of winter's snows in the far-off 
elevations of the Rocky Mountains. We see, year by year, the devastations 
caused by its wild waste of waters. We observe it, in its gentler moods, freighted 
with the products of many nations, destined to swell the commerce and add to 
the convenience and comfort of the enlightened and happy people occupying the 
environments of its picturesque shores. Generation after generation, age after 
age, witnesses the same occurrences ; and we are apt to associate this great river 
with the geological formations cut by its turbid waters for all past time. But, 
