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TABLE OF CONTENTS. 



ARKANSAS. 



Owen'k views in regard to the crystalline rocky of this State ; ho holds that they are 



eruptive, 482. 



MTSSOITFJ. 



Nothing definite known in regard to the crystalline rocks of this State, except that 

 most, if not ail, of them are eruptive, 482 ; they have heen assigned to the 

 lluronian and Laurcntian on lithological grounds solely, 482. 



MICHIGAN AND WISCONSIN. 



Koference to work recently published hy AVaj^sworth in regard to the geology of 

 this region, '182. Ago of tlic cupriferous rocks of Lake Superior discussed, 

 482-494; evidence ohtahied on hraiK'h of Torch lUver, 482-485; nature of 

 these rocks indicated, 483 ; the facts discussed, 484 ; conclusions reaclu;d, 485. 

 IiiviNo, in 1873-74, on the relations of the Lake Superior rocks, 485, 48t5 ; 

 he adopts a diirerent theory, in part, in 1879, 48G ; Swkkt states facts in o])po- 

 sition to the views of Irving, 48G ; our explanation of the phenomena, 487. 

 luviNG finds evidence in support of his views at the Dalles, 487 ; Ciiamiseiilin 

 holds the same opinion of this locality, 488. Selwyn, in 1882, states his views 

 as to the age and I'clations of the Lake Su2)erior rocks, which he had previously 

 called iJuronian, 488; these views identical with those of Fostek and W hit - 

 KEY, puhlishcd in 1850, 488. InviNG replies to Selwyu, 489; Wadswortii 

 replies to Irving, 489. IIt:nt, in 1883, states that Logan, in 1863, i)ut forth 

 conclusive evidence that the cupriferous rocks of Lake Superior underlaid, un- 

 confoi'mably, Ihc Potsdam sandstone, 489 ; Wadswoutii points out that Logan 

 brought no such e\'ide]iee, 489. N. IL Wincuell agrees with Foster and 

 "Whitney, and with Selwyn, 480. Chambehlin sums up his reasons for sup- 

 posing the Keweenaw rocks distinct from the adjacent sandstones, 489, 490 ; the 

 errors in his reasoning i)oiuted out, 490. Msu'int of the facts at the Taylor's 

 Falls locality, 490 ; assumptions of the Wisconsin geologists, 490 ; what Owen 

 Siuv tlu're in 1850, 490, 491. Observations of Kloos, iu Report for 1881, 491. 

 N. 11. WlNCUELL thinks the sandstone at this locality more recent than the 

 Potsdam, 491. Errors faPen into byluviNG and CiiAMliiouLiN poiut(Ml out, 

 491. The so-called "Kcwcenawan Scrips" owes its origi?i to incorrect observa- 

 tions, and ttroucous deductions, 491, 492; N. II. AVinciiell, in 1881, gives a 

 sumniary of the opinions held regarding the copper-bearing rocks, made up from 

 one ]U-eviously p\iblish(^d by Wadsworth, 492. AVadswokth iK)Uits out the 

 ignuriuice of the primdplcs of geology and litliology displayed by Bj-ooks and 

 Pumixdly, 492 ; they boiTow largely irom FosTKii and Wjjitnjcy's nia,p without 

 giving any credil, 492. Romixoek on the A/oic ]-ocks of Micldgan, 492, 493 ; 

 his views in regard to the eruptive chai'acter of the granites, 493 ; liis ]>rp.u]iar 

 thc.ori<is of tlu; eruptive rocks, 493, 494 ; his observations iu the Menoniineo 

 region, 494. Discussion of the origin ol' tiio iron ores in a previous publication, 

 by WAnswouTiJ, referred to, 494. The views nuuntnined by Fosteii and Whit- 

 ney, find by Wadhwoutii, sutttaiucd'by Selwyn, 494 ; these views opjjosed by 

 DaiNA, 494 ; his reasoning criticised, 494 ; N ewijejiuy also expresses his opinion 



