174 Review of Geinitz on the rocks and fossils of Nebraska. 
shells of this type, in 1864, with authentic European examples 
of the type of Bronn’s genus Monotis (M. speluncaria of the St. 
Cassian beds), the writer was led by the very nearly equivalye 
character, and entire absence of any traces of a byssal ema 
systematic classification of all the various eoctpe of the te 
lade, would forbid such an associatio 
ses those who hold that a _ classification — the 
at one time even referred it t to the genus Solen 
* This Jour., II, xxxvii, 
+ The note of on only Ghoti ba age in which Cee proposed the Pooeggh een 
i op Deutsch. g eol. Gesselsch, xiv, p. , . 10), being unac 
ype. e same grounds, propose” — 
Aus, in 1864, Beyrich’ 8 aa for both of these goad 
Ww f 
manifest that such distinctions are attracting the attention of systematic worker 
every eneee For instance, Laube adopts Cassianella as a good genus in his beautiful 
M h of the St. Cassian fossils recently publi lahed. He also there 
arentl charact f which the ) 
vo Pp good racters, 80° 
ve y ! ers, a genus Hdrnessia, for a Wee oy) eager 
s probable 
socialis of authors is the types though it 
present 
thi 
R teris, tblished in the Califor 
recrtlas thalias extorial ciate 
