94 THE MAKQUETTE IliONliEAlUNG DISTiaCT. 



operations of the district. Part 1 mid the remainder of Part II deal 

 largely with a theory to account for tlic deposition of the ore l)(>iH('s. 



The general geology of the district is described as in previous articles. 

 The Laurentian rocks are apparently regarded as metamorphosed sediments, 

 for it is related that "the beds of rock constituting the system are usually 

 tilted at higli angles, the whole series having been upturned and flexed, 

 broken and displaced, until little evidence of the original deposition in 

 horizontal strata remains." The Huronian rocks were observed to be tilted 

 nearly vertical. "They have l^een raised into folds or crumpled into 

 gi'0U]JS of irregular flexure, forming a series of irregular synclinal troug'hs." 

 The diorites and diorite-sclnsts are believed to be the prevailing rocks 

 of the series, and apparently are regarded as sedimentary in origin. Con- 

 glomerates containing pebbles of jasper were found grading into quartzite. 

 The ore bodies lie in the strata, forming minor folds. 



The most interesting- portions of the paper are those dealing with the 

 character and origin of the ore bodies. The Champion, ilichigamme. Lake 

 Su})erior, New York, Cleveland, and Jackson mines are described l>riefly, 

 and some points in their geology are touched upon. At the Michigamme 

 mine the chlorite pseudoniorphs of garnet were found bv Messrs. Dawes and 

 Oothout (pp. 46-47), but their nature was regarded as di)ul.)tful, since most 

 of them were thought to be monoclinic in crystallization. This, of course, 

 is an effect of the distortion to wliicli tlie crystals liave been subjected. 

 Messrs. Crocker and Porter examined the Jackson mine (pp. 107-109). 

 Here they found great complications in the stratigraphy. The "ore masses 

 were deposited in the jasper by some action of water, and over and between 

 them layers of 'soap rock' were deposited." 



The descrij)tion of the occurrence of the ore bodies in the Champion 

 mine, by C. Q. Payne, gave Prof. H. S. Munroe an opportunity to suggest 

 a theory for the deposition of the ore. Payne states that the Champion 

 mine deposit lies in one of the minor folds of the iron-bearing rocks. It 

 consists of a number of overlapping lenses, with the west end of one lens 

 usually lying to the north side of the next western lens, and overlapping 

 the underlying lens on the hanging-wall side (see fig. 2). " The foot wall 

 of the ore bed is dioryte and the hanging wall quartzyte. Chloritic schist 



