St. Peter's Sandstone. 



123 



again there occur certain transition beds, of which it is diffi- 

 cult to say whether they should be referred to one or the other 

 formation. 



At Seward's quarry, about two miles from Ripon, Wisconsin, 

 the junction between the St. Peter's and the overlying Trer.- 

 ton is well shown. It is here a very friable sandstone, varying 

 in color from yellow to brown. The upper layers, just beneath 

 the limestone, contain concretions or nodules varying in size 

 from half an inch to six inches in diameter. The sand is 

 irregularly stratified. In places it is white, but it is generally 

 more or less stained. The separation between the limestone 

 and the sandstone is distinct. The lower layers of the former 

 contain more or less sand, and are in thin courses one-half to 

 one and one-half inches thick. Above they become -heavier, 

 from four to six inches, but do not seem to be fossiliferous. 

 About fifteen feet of the sandstone is exposed. A short dis- 

 tance from this quarry is another exposure of the sandstone 

 about twenty feet high. Xo limestone capping is present. 

 The sand is often banded with red, while white and brown 

 streaks sometimes alternate. It contains a few concretions 

 near the top, below the junction with the limestone. 



At Mitchell's Glen, about four miles from Ripon and a mile 

 from Green Lake, both the Trenton and the St. Peter's occur. 

 The limestone is separated from the sandstone by transition 

 beds about two feet thick. The upper one of these is quite 

 sandy, as is also the lower, but the intermediate stratum, 

 about a foot thick, is a solid, more or less calcareous mass. 

 The St. Peter's proper is more or less friable, and white, 

 yellow or brown in color, more generally one of the latter. 

 The outer surface hardens on exposure, but in places it can 

 be taken out with a spade. At one point in the Glen is a 

 perpendicular fall of about fifty feet, at the bottom of which 

 is a pool of water. The sandstone is here exposed in vertical 

 walls on either side of the Glen to a height of seventy feet, 

 capped by layers of Trenton limestone. The bedding of the 

 sandstone is very irregular, dipping at various angles and in 

 different directions. Numerous large springs of clear, cold 

 water gush out from the sandstone walls. They probably 

 mark the approximate place of junction with the Lower 

 Magnesian. Xo fossils were observed by the writer. 



