ON OCONTO AND WOLF RIVERS. 



459 



pure a white. It weathers brown and red, from a mixture of iron, that does not 

 appear to the eye in the fresh fracture, and crumbles into sand. 



The upper ledge is more compact, but still soft, and not so white. Interstratified 

 is a thin calcareous bed, in which the structure is completely oolitic. There was 

 no apparent dip to the strata, and the exposure was very limited. 



The next place where we were so fortunate as to get a sight of this rock, is on 

 Section 13, Township 22, Range 16 east, on Wolf River, near Bruce's saw-mill, 

 about twelve miles northwest of Grand Chute. Here the calcareous sand-rock of 

 Oconto Falls is seen on the soft gray sand rock, as set forth in the following 

 section. 



Feet. 



1. Red clay, on the top of the bluff. 



2. Yellowish-gray calcareous sandstone-rock of Ocouto Falls, . . '20 



3. Slope, concealed, . . . . . . .20 



4. Surface of sand-rock of Oconto River, visible, .... 20 



The bed of Wolf River is but little elevated above Lake Winnebago, at the entry 

 of Fox River, distant in a direct line about thirty miles ; by the river more than 

 twice that distance. The water has very little current, so that I estimate its descent 

 at fifteen feet, the surface of the sandstone at sixty feet more, and the surface of 

 yellowish-gray calcareous sandstone (2), at forty more; making one hundred and 

 fifteen feet above Lake Winnebago, or two hundred and eighty feet above Lake 

 Michigan ; and this is apparently as high as any land seen between the Oconto 

 and Wolf Rivers. Concealed in the slope (3), is probably an alternation of siliceous 

 and calcareous strata. The calcareous sandstone (2), is overlaid with ten to 

 fifteen feet of sandy drift, which frequently covers the red clay in low ridges, and 

 furnishes, by mixture, a superior soil. 



About six miles southwest by west, in Township 22, Range 15, half a mile 

 south of the Wolf River, the same rocks may be seen in a bluff, facing north, for 

 several miles in length, in the same order, and at about the same elevation. 



Probably some of this rock may be found that will slake into lime when burned, 

 but I saw none that I thought would. Its composition is not uniform. No fossils 

 were seen. A bluff of this yellow calcareous sand-rock is reported as existing in 

 the bend of Fox or Neenah River, five miles north of Lake Apukna or Puckana, 

 Township 16, Range 11, which is about on a line to the southwest through the 

 two locations just described. The extension of the compact, yellowish, sandy lime- 

 rock to the west presents more calcareous matter, and becomes a true limestone. 

 Mr. Lapham observed the junction again at Fox Lake, in Township 13, Range 13, 

 Marquette County, and also in Township 10, Range 10, Columbia County ; so that 

 the line of junction may be approximately laid down to the waters of Rock River. 



Remarks upon the Equivalency of the Eastern and Western Rocks. — The vast field 

 of sedimentary rocks in the United States, embracing the States of Tennessee, 

 Virginia, Kentucky, Pennsylvania, Ohio, Indiana, Illinois, Missouri, New York, 

 Michigan, Wisconsin, and Iowa, the Territory of Minnesota, and the Province of 

 Canada, show everywhere the same general geological features. 



