rNTERESTING LOCALITIES OF ISHl'EMlis'G EOKMATION. 437 



as 2 feet in diameter. Also, tlieve are 2)reseiit a few i)el)l)les wliicli ai)j)ear 

 to be derived from the giieissoid granite of the Basement CJoni[)k'.\. At the 

 exposure nearest the jas])er is seen a distinct cleavag-o parallel to the side 

 of the Rei)ul)lic tongue, while the peljbles and bowlders are eoneentrated 

 into l)auds which cut across this cleavage, although tlic longer diameters of 

 the flattened pebbles are in the plane of cleavage. In all i)robal)ility these 

 pebbles were deposited with their longer axes parallel to the bedding. 

 They have, therefore, been rotated to their present position, or have been 

 flattened by ])ressure, or lioth have occurred. A close examination of the 

 jasper below shows that rotation has probal)ly taken place to some extent 

 Here the folding was so sh;u-i) as to bend the once regular belts of jasper 

 into zigzag bands, more nearly j^arallel to the cleavage than to their 

 original bedding. We therefore conclude that the pebbles of the con- 

 glomerate have been revolved as well as flattened. The quartzite and 

 conglomerate are also found at various places from the Republic mine to the 

 village of Republic, along the west side of Republic Mountain. Wherever 

 the contact is found between the Ishpeming and Negaunee formations the 

 latter is eroded, the former is a conglomerate bearing numerous fragments 

 of the latter, and there is a slight discordance between the two formations. 

 At one place on the east side of the trough, as a result of faulting, the contact 

 is a double one, a quartzite tongue appearmg within the jasper. The nature 

 of the contact between the two formations and the origin of this tongue 

 are fully discussed by H. L. Smyth in another place. (See pp. 542-047.) 

 The conglomerate grades up into a gray quartzite or quartz-schist. 

 This is in some places sufficiently coarse grained to show distinctly the 

 fragmeutal character, but at certain places it becomes novaculitic m appear- 

 ance, being- apparently composed mainly of the individual grains derived 

 from the Negaunee jasper. The quartzite is more or less Impregnated 

 •with magnetite. The quantity of this mineral lessens, upon the whole, in 

 the higher horizons. Also, in the quartzite at one place is a considerable 

 quantity of epidote, which in some specimens is sufficiently abundant to 

 give a distinct greenish tint to the rock. The quartzite in its ;q)per part 

 passes into a fine-grained, micaceous quartz-schist, and this into the mica- 

 schist of the Michig'amme formation. 



