1884.] 179 [Wadsworth. 



composed entirely of Azoic debris it is in perfect accord with my 

 observations that the eastern sandstone underlies the copper- 

 bearing rocks, and is opposed to Irving's view that it abuts against 

 these rocks and is made out of their ruins. I also have before me 

 specimens that were selected in the quarry expressly to show the 

 difference between the true bedding planes and the joint planes. 

 This angle as measured on one specimen is about 18°, but in 

 others it is less. 



Irving is further mistaken in his statements that he was the first 

 to point to the presence of acid eruptives in the so-called Ke- 

 weenawan series, and that Foster and Whitney regarded all the 

 acid or jaspery rock as metamorphosed sandstones, and all the 

 conglomerates and sandstones as friction detritus. 1 



I further have reason to object to Professor Irving's general 

 method in the first part of his report inasmuch as it is written so 

 as to convey to persons not familiar with the literature of Lake Su- 

 perior geology, the idea that he was the first to microscopically 

 study the Keweenawan felsites, granites and quartz-porphyries, 

 when instead they were first so studied by myself. 2 There is al 1 

 the greater reason for a protest against such a method of writing 

 since I have evidence that it has resulted in misleading persons in 

 the past. Still I have no complaint to make of the latter part 

 of Irving's report or of his papers since 1883, on this score. In the 

 final report, however, Irving makes statements regarding the views 

 of Foster and Whitney, and my writings, that are so incorrect, 

 that it is difficult to find excuse for them, except on the supposi- 

 tion that he quoted us from memory, and that his memory is de- 

 fective. Again Irving's statements of the views and labors of 

 others are often incorrect or partial and misleading. I may cite 

 for examples the assertions that Rivot only had maintained the 

 metamorphic (sedimentary) origin of the traps ; that Pumpelly 

 and Marvine first recognized definitely that the amygdaloids were 

 the upper portions of the trappean beds ; that Marvine made the 

 first plainly and thoroughly worked out argument from structural 

 characters alone in favor of the lava-flow origin of the traps ; that 



1 Geology of Lake Superior, Part 1, 1850, pp. 58, 59, 70, 71, 78, 79, 103, 109. 

 2 Irving has partially rectified this in a foot-note appended to his final publication,- 

 issued since this paper was read. 



