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C. A. White—Molluscan Fauna of the Laramie Group. 209 
. Ostrea Wyomingensis Meek. 
Anomia micronemu Meek. 
ite. 
. Corbicula cytheriformis Meek and Hayden ? 
. Odontobasis buecinoides White 
. Melania Wyomingensis Meek. — 
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This Mexican collection, so far as it goes, is an almost exact. 
duplication of the Laramie molluscan fauna of the Bitter Creek 
series as found at Rock Springs, Point of Rocks and Black 
Buttes, in Southern Wyoming, points which are more than a 
thousand miles north of the Mexican locality. The specimens 
sen y No. 1 
original locality at Point of Rocks. Those of No. 2 are small 
examples such as are found at Rock Springs. The specimens 
o. 3 are merely fragments, but ve are presumably iden- 
tical ‘with Modiola regularis White, which occurs at Rock 
Springs. Those of No. 4 do not vary se poe from the 
type-specimens, which were found at Point ocks. 
The Corbicula of No. 5 is closely like ot toh which I have 
referred to C mb, pater found at Point of Rocks, but it is a 
little more angular upon ts posterior slope. No. 6 cannot be 
separated from the type siesnhonk of Odontobasis buccinoides 
ee were found at Point of Rocks. The specimens of Melania, 
. 7, present some variation from the type specimens that 
Weis found at Black Buttes, consisting mainly in their shorter 
form and the more pronounced character of the ornamentation. 
They are, however, regarded as of the same species, and their 
variation from the type spatinen is no greater than the varia- 
tion which they present among themselves. In short, the simi- 
larity of the Mexican and eee ng | ae = paeteeelats close, 
Group was deposited, and its separateness from the faune of all 
other North American groups of strata. 
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