GEOLOGICAL EXPLORATIONS AND LITERATURE— 1801. 125 



Ot" tlicsc till' author s^ays: 



The oocasioual survival of the characteristic diabase structure even in some of 

 the more foliated forms, taken in connection with their evident identity with and 

 gradual transition into the massive varieties, appears to be suflicient proof that, 

 with the excejition of certain unimportant tufl' deposits, these green-schists have 

 been derived from basic eruptives through the agency of intense mechanical and 

 chemical action. (P. 165.) Originally [they were] massive basic Hows. (P. 103.) 



The <'Teenstoiies of the Western or Ne<>aunee area, tlie second chosen 

 for examination, are Kkc tlie scliists of the Southern Manjuette ai-ea, while 

 those of the area north of Dead Ri\er are essentially similar to the rocks 

 in the Northern Marquette district. 



Of the Deer Lake area Williams has little to i-ccord. A transcrii)- 

 tion of portions of Irvinj^'s fi(^ld notes d('scril)es this area as underlain 

 bv the jirecnstone-couglomerates referred to in his pul)lished papers and in 

 the articles of Uominger, N. H. Winchell, Alexander Winchell, and others. 

 Williams recognizes these as composed of volcanic detritus, ejected hj' an 

 exjtlosive force at the earth's surface. He calls them agglomerates, which 

 term is used "to designate a tumultuous assemblage of volcanic ejecta- 

 meuta, bombs, foreign Idocks, etc., of all sizes and shapes, cemented by a 

 fine-grained paste of volcanic ash" (p. 1 !>()). 



Van Hise, C. R. An attempt to harmonize some apparently conflictiug views 

 of Lake Superior stratigraphy. Read before Wisconsin Acad. Sci., December 30, 

 1890. Am. Jonr. Sci. (3), Vol. XLI, 1891, pages 117-137. 



In this article the author points out the significance of the existence of 

 the conglomerates abo^e the ore horizon. He calls attention to tlie fiict that 

 Foster, Foster and Whitne^^ r)rooks. K(Mninger, Wadsworth, Irving, and the 

 Wincliells had all recognized and described these conglomerates, and that 

 they all h;ul detected in them fragments of the underlying formations, but 

 the Wincliells onlv regiirded them as marking a break in the succession 

 of beds of sufiicient importance to warrant placing the rocks above and 

 below it in difierent geological ages. K. H. Winchell believed the break so 

 great that the overh'ing rocks were provisionally referred to the Potsdam. 



The author describes the occurrences of the conglomerate at the (rood- 

 rich, Saginaw, Fitch, Barron, Winthrop, Cascade, Wheat, Jackson, Lake 



