5U 



Report ok tup; State Geologist. 



precipitous face which looks like a fault scarp. Such faces are characteristic 

 of most of the ridges of the county and produce the same impression on the 

 observer as do those of Fssex county, which Kemp regards as of the Mock- 

 tilted type. 



The Catamount gabbro is of the anorthosite variety, and so thoroughly 

 granulated that large cleavage faces are seldom visible in the hand specimen. 

 Hence the prevailing color is white, the ferro-magnesian silicates not being in 

 large amount and always concentrated along planes, so that the rock is quite 

 gneissoid. Garnet is present, but not so prominent as in much of the 

 anorthosite. The thin section shows monoclinic pyroxene, hornblende and 

 magnetite. 



Not far above the limestone quarry, basic gabbro outcrops, but is so 

 poorly shown that it is impossible to ascertain its extent. It is composed of 

 augite, hypersthene, hornblende, biotite, garnet, magnetite and labradorite. 

 It seems to have been originally of the ophitic type as it contains some of the 

 diallage like augite, full of inclusions, which characterize that type. None of 

 the original idiomorphic feldspar remains, however, and most of the rock 

 seems to have undergone recrystallization. None of the minerals have 

 idiomorphic boundaries except the biotite, which does not appear as reaction 

 rims round the magnetite, but in thin plates distributed through the rock. 

 In fact there is no sign of reaction rims of any kind in the rock. In addition 

 to the above the same gabbroic gneisses are found interbanded with the other 

 gneisses of Series I that are found so commonly in the other townships. 



Series I \ \ No Palaeozoic rocks are to be found in the township although 

 the Potsdam sandstone almost reaches it on the north and east. 



Series V. Thirteen dikes have been noted in the township, all of which 

 are diabases. Three of the very narrow ones approach augite-camptonite by 

 the augite of the ground-mass becoming idiomorphic. Nos. 84 and 86 are 

 very typical diabases, furnishing quite fresh material. 



Series IV. The higher level of the sand deposits of the Ausable river 

 runs up the river some distance above Ausable Forks, at that point rising 

 some little distance above the river level. Just west of the Forks on the road 

 to Black Brook an excellent section, twelve feet in height, is exposed, which 

 is as follows, from the top downward : 



1. Soil. 



2. Coarse yellow sand w ith a few boulders % 2 feet 



Fine white sand with no boulders, 3 " 



I. Still', blur, jointed clay, weathering white, 1 " 



