BROADIIEAD — WELL AT ST. LOUIS INSANE ASYLUM. 



219 



The above Section with specimens would indicate the forma- 

 tions about as follows : 



3 

 4 

 5 

 6 



7 

 S 



9 

 10 

 i( 

 12 

 13 

 14 



THICK- 

 NESS. 



4a ft. 



So 



670 



93 

 421 

 148 



GEOLOGICAL FORMATION. 



Clays of "Bluff" 



Coal Measures 



Lower Carboniferous Rocks 



Chouteau Group 



Trenton with Black River and Birdseje 



First Magnesian Limestone 



133 Saccharoidal Sandstone 



517 Second Magnesian Limestone 



82 Second Sandstone 



838 Third Magnesian Limestone 



98 Third Sandstone 



384 Fourth Magnesian Limestone 



54 Potsdam Sandstone 



285^ Mostly all Granite, the lower 40 ft. being certainly 



j Granite ; the upper portion may be Sandstone . . 



TOTAL 

 DEPTH. 



120 ft. 

 790 



883 



1304 



1452 



1585 

 2102 

 2184 

 3022 

 3120 

 3504 

 3558 



3843^ 



In the above section, the thickness of the several Geological 

 Formations is made up from Mr. Atkinson's descriptive sections 

 and an examination of specimens from the borings. It may there- 

 fore be considered only an approximation, for in a deep well, 

 whei'e all material is brought up in a comminuted state, there 

 may be errors ; but from the data it as correct as we can make it. 



Two well-marked formations are recognized, viz., the red cal- 

 caieous beds at the upper portion of the Chouteau Group, and the 

 Saccharoidal Sandstone. They have formed the chief guides in 

 the construction of our section. An important fact is also brought 

 forth in the determination of thickness and extensive range of this 

 Sandstone, so useful for glass making, etc. 



For comparison, I give the following Tabular Statement of the 

 thickness of the same Geological Formations in different counties 

 of Missouri : 



