42 



at the contact is altered into a fine-grained 

 aggregate of very pale green pyroxene and 

 plagioclase, but a large included block of the 

 limestone-paragneiss series, intensely metamor- 

 phosed, has been caught up by the igneous mass. 

 The narrow defile occupied by the road near the 

 summit of the hill has for a long time been 

 287-79 m - known as the "Hole in the Wall." 

 463-2 km. This diorite (about lot 48) is composed essen- 

 tially of hornblende and plagioclase with a little 

 accessory iron ore and an occasional grain of 

 pyrite. The hornblende is pale green in colour 

 and somewhat fibrous in character, its appear- 

 ance suggesting its derivation from pyroxene, 

 although no trace of pyroxene now remains. 

 The plagioclase has undergone considerable 

 saussuritization, the resulting products being 

 mainly zoisite and epidote. It is probably the 

 rock referred to by Vennor in his report on the 

 geology of the district as "blotched diorite." 



The diorite from lot 49 is rather finer in grain 

 and more basic, the hornblende in well defined 

 individuals being much more abundant than 

 the plagioclase. Thin sections show the rock 

 to be made up essentially of hornblende and 

 plagioclase. It is much more altered than the 

 "Hole in the Wall" diorite and some of the 

 hornblende is undoubtedly secondary. 

 290-79 m. This diorite on lots 56 and 57 to the west of 

 468 k.m. the road and close to the township boundary 

 differentiates into a large body of titaniferous 

 magnetite opened up and worked at the Orton 

 mine. This mine is the property of the Tivani 

 Electric Steel Co. of Belleville, Ont. Two 

 analyses show the ore to have the following 

 composition: 



Iron 51-45 60-84 



Sulphur trace 



Titanium 7 '5° 7 '5° 



Nickel o-ii2 



Vanadium trace o- 11 



This ore has been used very successfully for 

 the manufacture of tool steel in the electric fur- 

 nace by the Evans-Stansfield process [12, p. 52]. 



