SHUMARD—GEOL. OF STE. GENEVIEVE. 411 
thickness of this formation in Ste. Geneviéve is about 130 
feet. 
Trenton Limestone.—This cs rae in the county under 
es presents the same characters as in Jefferson and Per- 
On the Isle au Bois, it appears a short distance above 
e mouth, and from thence extends south-eastwardly oecu- 
pring a belt of country from one to two miles wide. This 
ase nga one Establishment, two miles, and the Gabouri 
and a half miles, from the Mississi 
Bleck River and Bird’s-Eye Limestone. “These forma- 
tions have not been recognized, in this county, apctitenet from 
the Trenton. 
Maaenestan Lrvestone Senna’ 
The rocks of this series are extensively serene being 
ined over the whole middle and western thir d of the poeaty) 
Ist Magnesi imestone.—This member, in Ste. 
vive, consists couse of thin, even-bedded buff, and creat 
> Silic stone, passing sometimes into a 
at forms for the most part smoothly 
gentle pening from which the mig 
. characters, 
iy desoribed by Dr. Litton, in the 
— at 1 a peo ero le 
cad branches of the Inle na Bow 19 Aux Waseh_ 
