PETROGRAPHIC GEOLOGY AND DESCRIPTIONS. 449 



Quartzyte.] 



Remark. As the metamorphism increases in receding from No. 605, it is 

 probable that it is not due, on the north side of the dike, wholly to that dike, but 

 rather to the main dike or axis of Pigeon point, which, however, is not visible at this 

 place. These rocks, from No. 606, succeed each other in a downward order of 

 apparent stratification, receding northward from the dike No. 605. N. H. w. 



No. 612. QUARTZYTE. ( MetamorpJiosed. ) 



Pigeon point. Near the same place, at the little bay at the south end of the " Little portage." 

 Kef. Annual Report, ix, pages 69, 70; Annual Report, x, pages 57, 58. 



Me;/. Appears like the last but perhaps is more uniformly crystalline and 

 uniform in grain, and in color, though not so red as the last. 



.1/Vr. Reddened feldspar, occasionally striated, is the most abundant element. 

 Quartz is also abundant. Next is mica, apparently Muscovite. These three are 

 mutually interlocked in a granitic fashion, one being occasionally isolated within a 

 mass of the other. The mica sometimes is replaced by a greenish fibrous or plated 

 mineral, probably chloritic, with low double refraction and strong pleochroism. In 

 some considerable areas penninc, finely fibrous, with a dark-blue color of double 

 refraction is closely mingled with the feldspar and with the muscovite. These, with 

 a few grains of sphene and the coloring matter (hematite) constitute the rock. 



Age. Modified and crystallized Animikie. 



Remark. The relations of Nos. 607-612 to the dike and to the quartzyte cannot 

 be stated positively, for the whole situation is confused, yet the position of the beds 

 from which they are derived is such that they would succeed each other in descending 

 order northward. No. 604 seems to be the quartzyte hardened. It forms a surface 

 sloping to the lake. It is cut by No. 605, but as No. 605 rises five or six feet above 

 the lake it comes in contact on the north side with No. 606, which while so situated 

 as to be the apparent continuation of No. 604, has a very different lithology. It is 

 more like the rock No. 603, in its color and outward general character, but differs 

 microscopically. It is coarser grained than No. 604, but has free quartz and 

 hornblende. No. 606 overlies the numbers following to No. 612. These last oannot 

 be said unqualifiedly to come in the order numbered, but probably do approximately. 

 The layers are in strata that dip south or southeast, weathering out thin-bedded. 

 The samples did not come from successive beds, but rather at increasing distances 

 along the beach, somewhat descending in the strata. The most fragile of these 

 layers (Nos. 611 and 612) are at once followed by the pebbly beach where the portage 

 trail passes over to the north side. It was doubtless owing to the occurrence of 

 these soft beds, which rot and easily chip into pieces under the action of the water 

 and ice of the lake, that the break-down in the peninsula occurs here. They are due 

 therefore to the action of the main dike which forms the axis of Pigeon point, rather 

 so 



