Cretaceous in Minnesota. 349 



quarried at Austin and at points below in the banks of the 

 Cedar river, as well as by the sandstone seen at Fritz' quarry 

 on the Minnesota, a few miles below New Ulm. There is a 

 pebbly deposit in Fillmore county, associated with a white 

 sandstone, that also probably belongs to the Dakota Group. 

 The Fort Benton Group has been identified in the Sauk river 

 valley by a few fossils found in explorations for coala few 

 years ago. This rests on the authority of F. B. Meek. There 

 are also extensive clay and shale beds exposed along the Min- 

 nesota, and on the Cottonwood, embracing beds of lignite 

 that doubtless belong to the Fort Benton. At New Ulm is a 

 calcareous member, burned for quicklime, that probably rep- 

 resents the Niobrara 



Wherever this formation has been explored for coal in Min- 

 nesota, the results have not been encouraging. The lignite 

 varies from a cannel coal to charcoal, and is often injured by 

 clayey impurities, and by the presence of what appears to be 

 ashes. The difficulty and cost of mining are also increased 

 by the non-indurated condition of the overlying layers, ren- 

 dering it necessary to line by timbers, or otherwise support the 

 upper part of every opening that is made. Some of the clays 

 have been successfully employed in making pottery, and also 

 in the manufacture of fire-brick. 



To the drift the Cretaceous has contributed largely in the 

 State of Minnesota. Its debris is distinguishable in nearly 

 every county west of the above line. It is the source of 

 much of the clayey material of the boulder clay, and its alka- 

 line qualities are very perceptible in much of the surface wa- 

 ter. Superficially the Cretaceous has produced a greater ef- 

 fect on Minnesota than any other geological formation ; yet 

 its beds in situ are less frequently seen than any others. 



