p. 2

-787-

1849.

Proceeding west to Columbus (Sec. 13 T. 10 R. 12) we come upon the lower limestone "Calciferous rock" which is seen in the bed of the Crawfish Creek at the mill; and this rock shows itself as far as Sec. 27 T. 11 R. 10, where a wall reveals the sandstone, being the first seen on our route from Milwaukee. Fragments of an Oolitic limestone, or limestone with scattered particles of sand, were found in this vicinity, precisely like the layer seen at Janesville above the sandstone.

From this point to the Wisconsin river at Dekorra we traveled on a region of Sandstone which is the upper portion of the Potsdam, or Lower Calciferous. It is soft, friable, easily crumbling into sand. Colors, red, yellow, or white, of various shades. Occasionally a tinge of green.

At Dekorra the cliffs are entirely sandstone, soft, white and yellow.

From Dekorra we went to Fort Winnebago, where the Fox and Wisconsin rivers come so near together and thence up the "Piney Road" in a N.W. direction about five miles. All the way on sandstone. From information obtained here, I inferred the existence of a trap dyke" about three miles north of our stopping place and accordingly set out early in the morning with a guide to find it. He led me about four miles to some very high and steep, rocky bluffs which proved on examination to be only sandstone.

Immediately west of this place is a large, level country through which a slough winds its way without current, except in times of great rains, or wet seasons. This flat is said to extend across from the Wisconsin to the north fork of the Neenah river, it may at one time have been the channel through which the water