REPORT OF THE DIRECTOR AND STATE GEOLOGIST 1900 r3T 



Section west from Saranac Inn station, N. Y. C. & H. R. R. R. 



Unlike the previous sections this lies wholly well within the 

 anorthosite mass not approaching the boundarv' anywhere. 40 

 rods east of the depot is a small cut in ordinary anorthosite. The 

 first cut west of the station is 1^ miles distant and is again in 

 ordinary anorthosite (950), that is the rock consists wholly of 

 labradorite except for trivial amounts of augite, garnet, magne- 

 tite and pyrite or chalcopyrite, which seldom comprise as much 

 as 5^ of the rock and usually much less. The rock is much shat- 

 tered by closely repeated vertical joints in two sets, one set of 

 which is often curved, producing wedgelike blocks, and the 

 adjacent rock surfaces are commonly slickensided, showing that 

 we are dealing with a zone of slip faulting. A little over i mile 

 beyond is a 50 yard cut in precisely similar material, equally 

 shattered and sheared. 



At 2f miles from the station is another 50 yard cut in a ridge 

 which runs down with a cliff face to the north shore of Hoel 

 pond. The rock here (952) is more thoroughly granulated than 

 the preceding, but consists of 99,^^ labradorite, holding otherwise 

 a little pyrite, zircon, a few small augite inclusions and a little 

 quartz feldspar intergrowth of the quartz vermicuU type. The 

 rock is not so excessively jointed as in the previous cuts, being 

 more normal in this respect. Besides the two joint sets there is 

 also a slip cleavage giving slickensided surfaces. 



At a little more than 3 miles is a cut 120 yards long, again in 

 typical anorthosite (953) showing an interesting altered strip a 

 few feet wide in which the feldspar has wholly gone to scapolite. 

 This is much less altered than the general appearance of the rock 

 would indicate, though the scapolite fragments are kaolinized 

 outwardly and along the cleavage cracks. The alteration has not 

 wholly destroyed the original, opaque, rodlike inclusions of the 

 labradorite which appear here and there, sometimes quite numer- 

 ously, in the scapolite. Adjoining the scapolite strip, the anor- 

 thosite is excessively sheared, cleaving along slickensided faces, 

 which follow^ one another at intervals of fractional parts of an 



