238 
Geology of Southeastern Iowa. — Gordon. 
writes us that this well was put down to test for gas and oil 
and that the failure to find either — a result to be expected by 
those familiar with the stratigraphy of this region — was a great 
disappointment to the people of that place. 
KEOKUK, OTTUMWA. SIGOURNEY. 
Thick. Depth. Thick. DejHh. Thick. Depth. 
Drift. ... 23 ft 23 ft Drift... 98 ft 98 ft 
Surface BluflF . 25 ft.. 
Boulder clay 3".. 
St. Louis . . . Limestone 5 " . . 
Sandstone 5".. 
Limestone 12 ".. 
Keokuk— Shale.... 58".. 
Limestone 62 " 
Shale.... 10" 
Burlington- 
Limestone 110 
Shale (cal.) 65 " 
Kinderh'k— Limestone 10 " 
Shale . 195 " 
Hamilton— Limestone? 65 " 
Oriskany— Sandstone 20 " 
(sandy) 
Niagara— Limestone 55 " 
Sandstone 37 " 
Maquoketa--Shale 63" 
„ , „ ) Limestone 
Galena & ( 
25 ft 
28" 
33" 
170' 
180' 
290' 
355' 
365' 
560' 
625 ' 
700" 
737" 
800" 
Limestone 23 ' 
Shale 14 
Sandstone 30 ' 
Limestone 14 ' 
Shale 
Limestone 116 ' 
Sandstone? 30 ' 
Limestone 180 ' 
Limestone 15 ' 
Shale .... 160 ' 
Limestone(?) 
mixed with 
Sand 200 ' 
Limestone 150 " 9-55 ' 
90 
104' 
220' 
250' 
445' 
605' 
321' 
350- 
354' 
Sandy 
St. Peters— Sandstone 110 
L. Magnesian; 
940' 
10.50 ' 
Limestone alternating 
with Sandstone 
Lime and 
Sandrock 90 ' 
Sandstone 93 ' 
Slate 20' 
Limestone 100 ' 
Sandstone 122 ' 
Limestone 89 ' 
Shale ... 2' 
Limestone 1.32 ' 
Shale . . 29 ' 
Limestone 4' 
Shale ... 252 ' 
Limestone 229 ' 
Sandstone 41 ' 
Shale sandy 14 ' 
Shale 140" 1030^ 
Shale (?) 25 " 1055 ' 
(sandy below) 
Limestone 113 ft 1168 
Sandstone 107 " 1275 ' 
Shale 4" 1279' 
755 ft 1805 ft Limestone 
1045 
1138 
■ 1158 
1258 " 
1380 (?) Sandstone 
2077 ft 
j^OTE.— in some cases tne aetermmations given by the drillers are evidently mis- 
leading; as, for example, in the Ottumwa well at 220-250 is given a sandstone 
which doubtless is the Upper Burlington, which might easily be mistaken for sand- 
stone unless one were familiar with the rock. So also the classification in certain 
cases can onlv be made provisionally as where limestones of different formations 
follow each other, the driller gives it alias "limestone." In the main, however, 
the record may be relied upon. 
Geologists will at once recognize some features in the above 
records not heretofore given in Iowa geology. At Keokuk and 
Sigourney, as also in Washington,' the Devonian is underlaid 
by a bed of sandstone which we were at first inclined to con- 
sider the representative of the Medina of the eastern geologists, 
but on further study believe it to be the Oriskany as found in 
Illinois and adjacent states. It is probably confined to the 
south and east part of the state. It is separated from the 
sandstone of the Niagara at Keokuk by a limestone somewhat 
arenaceous which j)robably constitutes the upper portion of 
that formation. 
Another fact of importance brought out in the above records 
is the remarkable development of the Lower Magnesian series 
in this region. At Keokuk the drill passed 755 feet of this 
formation without completing it and at Ottumwa the record 
^ American Geologist, Jan. 1888. 
