218 RECORD OF DEEP- WELL DRILLING FOR 1905. 
"Trenton" — Continued. Feet. 
White to brownish limy sandstone 1 , 105 
Gray and brown shale 1 , 125 
St Peter: 
Red and white sandstone 1, 135 
Casing used, 10-inch, 300 feet; 8-inch, 338 feet. Main supply of water from below 
1,025 feet; water rises within 40 feet of surface; yield and quality not tested. Eleva- 
tion of well, 630 feet. 
Mr Ulrich says: "The crystalline limestone in this log [from 818 to 1,025 feet] indicates 
that there is no true Galena in this section, and that the equivalent but crystalline Kimms- 
wick limestone extends northward to this point. This is an interesting and important 
point that I had hitherto only suspected." 
46G. Well near Oskaloosa, Maliaska County. 
[Well begun and completed in 1905. Authority, 11. L. Purcell, driller. No samples. Geologic cor- 
relations by E. O. Ulrich.] 
This well penetrates the drift and rocks of Carboniferous age. - The white rock is thought 
to be Mississippian limestone, in which case the rocks above are to be included in the 
Pennsylvania n series (Coal Measures). 
Record of well 6 miles southeast of Oskaloosa. 
Recent and Pleistocene: Feet. 
Yellow loam and clay - 26 1 
Pennsylvania!): 
Black shale 26-31 
Gray shale with coal 31 - 46^ 
Black shale with coal. 46£- 85} 
White clay 85£- 93^| 
Black shale 93J- 97m 
"Bowlder" 97J- 99 1|| 
Black shale 99 -102 
Soft shale with coal 102 -106 
Black shale 106-116 
Sandstone 116 -121 
Light fire clay 121 -146 
White limestone 146 -166 
Dark sandstone 166 -169 
Mississippian: 
White rock; water-bearing 169 -221 
Rig used, cable. Casing used, 188 feet of 4-inch. Main supply of water at 215 fee ; 
Yield, 3 gallons per minute. 
4 TO. AVell at Davenport, Scott County. 
[Authority, H. W. Hambrecht, superintendent of L. Wilson Well Company, contractor. No sample 
(icologic correlations by E. O. Ulrich.] 
This is one of a considerable number of deep wells that have been sunk in the artesu 
basin that underlies Scott County, Iowa, and Rock Island County, 111., Davenport havii 
more deep artesian wells than any other city in Iowa. 
The rocks penetrated by this well include shales, sandstones, and limestones, ranging : 
age from Devonian to lower Ordovician. The formations arc, from top to bottom, Devo 
ian limestone, Silurian limestone, Maquoketa shale, " Trenton" limestone, St. Peter safi U j 
stone, Oneota limestone and sandstone (Ordovician). 
