and their Contact Zones. 67 



This is near the Old Fashion Reef, and about 55 chains 

 to the south-east of section No. 2. 



a. Grey felspathic quartz diorite. 



b. Similar rock with more dark-coloured mica ; and small, 

 fine-grained, dark-coloured inclusions. 



c. Similar rock with more mica. 



d. The rock from c extends to here, where there is a band 

 of aplite six inches wide dipping north-west at 60°. 



e. Aplite beds, the bedding and jointing indistinct, but 

 may be in accordance with that at d, and the jointing nearly 

 perpendicular to that direction. 



/. Some very irregular bands of schistose hornfels, say, 

 six feet in width, traversed by many very minute joints. 



g. Granitic diorite like that at d, but much decomposed. 



h. Hornfels commence here. The rock is very hard and 

 slightly spotted, but also in places schistose. 



Beyond this, to the north across the strike, the schists 

 gradually pass through the changes already noted. 



In Odell's Creek still further round the contact towards 

 Eureka, the contact of the igneous and sedimentary rocks is 

 well displayed. The latter are much broken up, crumpled, 

 and extensively altered. At some distance up the stream 

 the sedimentary beds are seen to be cut across by the quartz 

 diorites. The rocks resulting from these alterations and 

 interferences are varieties of hornfels, from a close-grained, 

 dark-coloured, crystalline rock almost resembling some 

 varieties of basalt, to a schistose contorted rock resem- 

 bling a fine-grained gneiss. 



In places the contact is sharp, in other places the rocks 

 interlock, and often the whole rock, igneous and sedimentary, 

 assumes almost the same character. Many of the fine- 

 grained inclusions in the granitic diorites along this contact 

 strongly suggest that they are portions of sediments which 

 have not been completely absorbed. 



The instances which I have now given will sufficiently 

 define and describe the group of contact schists, and are 

 applicable mutatis mutandis to all parts of the contact 

 surrounding the intrusive igneous masses. The diagrams 

 show the series of contact schists to include indurated or 

 silky slates, hornfels, and aplite, taking each of these to 

 include varieties which connect the whole. They are clearly 

 shown by their mode of occurrence, by the common direc- 

 tion of dip and strike, by the manner in which they 

 alternate with and pass into each other, by varieties, and 



