256 



THE GEOLOGY OF MINNESOTA. 



[St. Lawrence limestone. 



bottom of the quarries at Winona, constituting a highly prized building- 

 stone. These fine-grained layers are quarried at Dresbach by S. V. Brown. 

 They are from ten to twelve inches thick each, even and true, and make a 

 beautiful cut-stone. Above these the strata graduate into the more coarsely 

 textured, and often vesicular heavy stone, that more perfectly represents 

 the average characters of the St. Lawrence. In some places, before the 

 good quarry stone is reached, in ascending the bluff's, there is a series of 

 poor dolomitic irregular beds, somewhat lumpy. 



The exact contact of the St. Lawrence with the Jordan was observed 

 along the railroad east of Lewiston. The transition is abrupt from the 

 brecciated and concretionary, firm, upper strata of the St. Lawrence, to the 

 rusty and arenaceous layers of the Jordan. 



FIG. 10. VIEW IN GILMORE VALLEY. 



On some of the bedding surfaces of the layers quarried near Stockton 

 may be seen not only numerous fucoids, both coarse and fine, but other in- 

 distinct traces of fossils, the most conspicuous and distinct of which is a 

 loosely coiled shell about an inch or an inch and a half across from side to 



