38 IOWA ACADEMY OF SCIENCES. 



Keyes* has recently shown that the two limestones found in southeastern 

 Iowa, and long known as the Keokuk and Burlington, ai'e really conforma- 

 ble members of the same formation to which the name Augusta has been 

 given. 



Worthen.f in his notes on Washington county, calls attention to remark- 

 able thinning out of the Keokuk; it being greatly reduced or entirely absent 

 over the regions studied. This observation has, during the present field 

 season, been completely substantiated, not only for Washington, but Keokuk 

 county. These facts taken together, all point to the same conclusions: 

 that the first 89 feet of limestone pierced belongs to the Saint Louis, while the 

 Keokuk is represented merely in a few feet of the succeeding 168 feet of 

 strata. The two bands of heavy limestone comprised in the strata thus 

 referred to, the Augusta, are closely similar in lithological character, and 

 resemble the Augusta limestone of the region as nearly as can be determined. 

 At a depth of 342 feet a fossil, Rhynchonella sp. und., was brought up, it 

 being the only fossil preserved. Below this point the element of uncertainty 

 becomes greater. The succeeding 239 feet of shale is probably all referable 

 to the Kinderhook, though the thickness is somewhat greater than an exam- 

 ination of the Washington county outcrops seem to indicate. The 250 feet 

 of limestone which succeeds is most probably Devonian. The succeeding 

 30 feet of sandstone and 6 feet of limestone are more probably Niagara, 

 since Calvin has shown that the Niagara at Washington is arenaceous. It 

 is prossible, howevei', in this case, that the sandstone encountered may be 

 of Devonian age and represent the Montpelier sandstone. The overlying 

 limestone being the Cedar Valley. 



The Maquoketa shale seems, by comparison with neighboring i-ecords, to 

 be well recognized. 



The heavy limestone band, 285 feet, succeeding the shale is probably 

 representative of the Trenton and Galena, though it seems impossible to 

 draw a good line between them. 



The 115 feet of sandstone which succeeds seems to be the Saint Peter. 

 Beneath this for some distance no samples were obtained as the current of 

 water struck was so strong as to wash away all the drillings. The lower 

 position of the well yielded samples which an examination proved to be 

 limestone as Gordon surmised, and not sandstone as published. This seems 

 to clearly prove that the well ended in the Oaeota, though the top of the 

 formation was not definitely located nor was it penetrated, so that its thick- 

 ness under this portion of Iowa is as much a problem as ever. 



The well was sunk in hopes of obtaining strong flow of artesian water. 

 A moderate flow was obtained but has never been used to any great extent. 

 At 1,320 feet in the Saint Peter sandstone a vein of water was struck which 

 contained mineral matter and possessed a strong odor. At 1,360 feet in the 

 same formation an opening was struck and the drill suddenly dropped two 

 feet. A strong current of fresh water carried oft' all the samples and the 

 water increased to the depth of 1,388 feet, when it flowed over the top of the 

 well while drilling and stood within thirty feet of the top when the drill 

 was at rest. No more water was struck from here to the bottom of the 

 well. 



♦Keyes, Geological Formations in Iowa (Iowa Geol. Sur. I, First Ann. Rep., 1892, 59- 

 60, Des Moines, 1893). 



tWorthen, Geol. of Iowa, vol. I, p. 244. Albany, 1858. 



