r44 NEW YORK STATE MUSEUM 



in garnet, and witli many and large labradorite augen remaining 

 (904). Beyond, the rock passes into ordinary anorthosite. 



Summary of section. This section conies nearest of any to 

 affording a transition from anorthosite to augite syenite. The 

 syenite, shown best in the cut at 3^ miles (906), is unquestionably 

 the same rock as that found in dikes cutting the anorthosite in 

 the Saranac (805A) and Saranac Inn (954B) sections. Yet it is 

 here found as a border phase of a large syenite mass. Further, 

 the rock from the cut at 4 J miles, though to be classed with the 

 anorthosite, shows strong leanings toward the other rock and is 

 an unmistakable intermediate type, as the chemical analysis will 

 more strongly emphasize. It ie also very like the border rock 

 near the reservoir at Saranac (973). The two furnish strong 

 evidence of the close relationship of the two rocks, the anortho- 

 site and syenite. 



Section from Tupper Lake village toward Wawbeek 



Just in and about Tupper Lake village are many exposures of 

 augite syenite gneiss. In the village a quarry has been opened 

 for road metal and foundation stone, and this furnisheis the 

 freshest and most satisfactorymaterial (999). It is in all respect* 

 quite typical augite syenite gneiss. There is present some 10^ 

 of dark eilicates, hornblende, augite, magnetite and bronzite, in 

 order of abundance, though the quantities vary much from place 

 to place. There is considerable zircon and but little apatite, as 

 is usual in this rock. Some 5,< to 10;^ of quartz is present and 

 the remainder of the rock consists of feldspar, mostly rather 

 poorly marked microperthite, though the micrographic inter- 

 growth is at hand as well and sometimes the two are combined. 

 There is also a little oligoclase. 



These syenite exposures only extend for J mile east of the vil- 

 lage, and beyond for 3 miles no rock protrudes through the heavy 

 drift filling. But not far south of the road a ledge of the same 

 rock shows by the river, 2 miles from the village. 1 mile farther 

 up the river, the first anorthosite is found, so that we have here, 

 along the boundary, a gap of a mile in which no exposures are 

 forthcoming. 



