IOWA ACADEMY OF SCIENCES. 37 



While the unreliability of records derived from the ordinary or churn drill 

 is fully recognized, it is believed that the care with which these samples 

 were selected and preserved, at least considei'ably reduces that element of 

 doubt. Previous accounts of this record have been published in the local 

 newspapers, and re-published by C. H. Gordon in the American Geologist." 

 Recent studies in the region, as well as a revision of the material, give, 

 however, considerable information not available at that time. 



The following table represents the record as i-ecently determined, as well 

 as the interpretation: 



1- 98 Earthy matter 98 Drift 98 



98-120 Limestone, impure, eartliy 22 



120-135 Limestone, ctierty 15 



13,5-155 Sliale, calcareous 20 



155-165 Limestone and shale 10 



165-170 Limestone, liard, bluish gray 5 



170-187 Limestone, cherty, light 17 Saint Louis... 89 



187-189 Shale 2 



189- 314 Limestone, hard, white with brown particles 125 



314- 315 Shale, dark green 1 



315- 356 Limestone, grayish white to drab, Zij/»c?io»efJa at 342 ft.. 41 Augusta 168 



356- 554 Shale, soft, green 198 



554-556 Limestone ... 2 



55(5- 5S5 Shale, soft, green 29 Kinderhook.229 



585-835 Limestone 250 Devonian 250 



835-865 Sandstone 30 



805-871 Limestone 6 Niagara 36 



871-1030 Shale, blue argillaceous 151 Maquoketa..l51 



1030-1275 Limestone 245 



1275-1281 Sliale 6 Trenton and 



1281-1315 Limestone 34 Galena ....285 



1315-14C0 Sandstone 115 Saint Peter.. 115 



1430-1717 287 



1717-1888 Limestone 171 Oneota. 



A comparison between this and the previously published record shows 

 several discrepancies. The drift is in both cases given as 98 feet deep. 

 The next 89 feet is now referred to as the Saint Louis, whereas it was 

 formerly considered to be Keokuk. There are a number of reasons for 

 this change. In the first place, an examination of the samples shows 

 that the beds are not a single homogeneous limestone as represents the 

 Augusta of this region, but are made up of alternating bands of limestone 

 and shales such as compose the Saint Louis. It is also worthy of note that the 

 particles of limestone preserved are of the tine grained, compact character 

 and ash to brown color so constantly seen in the Saint Louis of this immediate 

 region, and not of the coarser crystalline variety shown in the nearest 

 exposures of Keokuk. 



The topographic features also bear out this assumption. A line of levels 

 shows that the mouth of the well is 118 feet above the bed of the river two 

 miles south of town. Saint Louis limestone is exposed along the river, reaching 

 here a height of nearly twenty feet, or about what it would be if on a level 

 with the strata found in the well, which are referred to the same age. 



♦Gordon, Notes on the Geology of Southeastern Iowa (Am. Geol.. IV. 237-239, 1889.) 



