Wadsworth.] 174 [April 16, 



seashore bluff. These observations also proved that at the birth- 

 place of the "Keweenaw an Series" that formation and the "eastern 

 sandstone" were one and the same. 



This evidence has been recently examined by Professor E. D. 

 Irving and the results published in the "Third Annual Report of the 

 United States Geological Survey." Irving, who was and is a warm 

 advocate of the integrity of the Keweenawan Series, admits the cor- 

 rectness of my evidence and argues that for some distance below 

 the Douglass Houghton Falls the copper-bearing rocks exist, as 

 stated by myself. He then abandons the idea that an old shore 

 bluff exists at the falls but places such a cliff some distance below 

 nearer the lake. Irving states that the rocks are here covered for 

 some two hundred paces, but that below this space the eastern 

 sandstone appears dipping from two to five degrees. He also as- 

 serts that I bridged in my imagination this covered space, and 

 united without evidence this low dipping eastern sandstone with 

 the more steeply dipping Keweenawan series below the falls ; 

 this however did not prevent Irving's imagination from placing be- 

 tween the two observed points the hypothetical sea-beach cliff, 

 which other observers had placed above at the falls. If we care- 

 fully read Irving's published works it will be seen that he no more 

 knows that the sandstones below the covered gap are distinct from 

 the rocks above, than I do that they are the same, according to his 

 own statement of my observations. Since the question now turns 

 upon the manner in which my observations were made, it is impor- 

 tant to know how our geologist in Wisconsin could allow himself 

 to state so positively what I did in that ravine walled by high banks 

 and concealed in the forests of Northern Michigan ? For his state- 

 ment that I imagined the connection between this eastern sandstone 

 and the so-called Keweenawan Series is entirely erroneous ; since the 

 sandstone seen by me to dip five degrees to the northwest I found, 

 by digging in the stream and on the sides of the ravine, to under- 

 lie others, and those in their turn were traced by digging until 

 it was proved that all formed a continuous series with a grad- 

 ually increasing dip up to the falls themselves. By actual inspec- 

 tion of the uncovered rocks and their superposition above one 

 another, the writer proved then that no such bluff, as Irving im- 

 agines, exists in the locality. 



It is to be remembered that the exact spot at which the Douglass 



