146 S. Powers — Granite in Kansas. 



Art. XIY. — Granite in Kansas : by Sidney Powers. 



During the last three years granite has been occasionally 

 encountered in wells drilled in Nebraska and in the east-central 

 portion of Kansas over an area extending from near Eldorado, 

 Kansas, to Pawnee County, Nebraska.^ These wells, starting 

 in the same Pennsylvanian horizon, encounter the igneous rock 

 at depths of 550 to 2500 feet, while other wells within a short 

 distance may be drilled to a greater depth and find only sedi- 

 mentary rocks of the normal Paleozoic succession. The 

 granite, a medium-grained, pink, biotite type, is not intrusive 

 into the Pennsylvanian and must be of Early Paleozoic or of 

 ]3re-Cambrian age. 



In a recent paper, Twenhofel has called attention to granite 

 porphyry, chert, and quartzite bowlders in (?) the Pennsyl- 

 vanian strata near Pose, Woodson County, southeastern 

 KansaSjf suggesting that the origin of the bowlders may be 

 similar to the origin of the granite encountered in the wells. 

 Twenhofel presents strong arguments to show that these 

 bowlders were deposited contemporaneously with the LePoy 

 shales and sandstones of Pennsylvanian age. He also believes 

 that the bowlders reached the positions where now found 

 through the agency of ice, because " the sediments with which 

 they appear to be associated were deposited in quiet waters — 

 waters absolutely unable to transport bowlders of the size of 

 those which are present.''^ 



If the bowlders are in Pennsjdvanian strata it does not seem 

 impossible that they were derived from a buried knob of igne- 

 ous rock such as postulated below. The bowlders are on a low 

 anticline but Twenhofel does not believe that they can have 

 been derived from a granite mass in this region in Pennsyl- 

 vanian time, because "the strata of the region are almost 

 horizontal and if the granite mass projecting above the present 

 level of the bowlders were once present, it seems that some- 

 where in the region it should still project through the sedi- 

 ments which lie at the same level as the bowlders. There is 

 absolutely no evidence that such is the case."§ However, if 

 granite is encountered in wells in Kansas at a depth of only 

 550 feet, it is quite probable that at places granite occurs still 

 nearer the surface and it might have been undergoing erosion 



* E. Haworth, On Crystalline Eocks in Kansas, Univ. Geol. Snrv., Kansas, 

 Bnll. 2. 1915. He describes some of the occurrences, but denies the presence 

 of granite in the wells. 



f W. H. Twenhofel, Granite Bowlders in (?) the Pennsylvanian Strata of 

 Kansas, this Journal, xliii. pp. 3G3-380, May, 1917. 



X Idem, p. 372. § Idem, p. 372. 



