Contributions to Paleontology. 



191 



" that of the Red sandstone. It has already been stated 

 " that the Red sandstone of the south coast dips regularly 

 " northerly, while the upper or Gray sandstone dips equally 

 " regularly south or southeasterly ; in which respect the 

 " last mentioned rock conforms to the limestone resting 

 " upon it, while it rests itself upon the uptilted edge of the 

 "red sandrock below." 



"We have therefore an unequivocal assertion of the un- 

 conformability of the upper sandstone with the rocks 

 below. 1 



Dr. Owen, at a later period, in making investigations 

 from the Mississippi valley to Lake Superior, has very 

 clearly shown the probability, if not the ascertained cer- 

 tainty, that the Red sandstone of the western part of Lake 

 Superior is inferior to the fossiliferous sandstones of the 

 Upper Mississippi and St. Croix valleys ; and he suggests 

 that the latter may lie unconformably upon the disturbed 

 and uptilted formation below. 



From the disturbed and highly inclined position of the 

 interstratified conglomerates and sandstones on the north- 

 ern and eastern shores of Lake Superior, Sir William 

 Logan has become convinced that these deposits are older 

 formations, and unconformable to the sandstone of the 

 south shore from Keweena point to the eastward. 



The testimony, therefore, of all those who have investi- 

 gated the localities, concurs in recognizing two or more 

 eras in the deposition of the conglomerates and sandstones 

 of the Lake Superior region. And while the older beds 

 of that area are apparently below the fossiliferous beds of 

 the Upper Mississippi valley, the newer sandstone of the 

 St. Mary's river, which is apparently of the age of the St. 

 Peters sandstone, or the Chazy formation, will be found 



1 It would appear, however, that at a subsequent period, Dr. Houghton 

 was induced to regard the conglomerates and red sandstones and shales 

 which are penetrated by trap rocks, to be of the New Red sandstone. 



