PETROGRAPHIC GEOLOGY AND DESCRIPTIONS. 297 



Diabase. Bornite.] 



No. 278. DIABASE. 



"Is from the east end of the long island west of Governor's (or Susie) island, next south of No. 277; from 

 the main dike of the island." From the long island in N. E. J4 sec. 6, T. 63-7 E. 

 Ref. Annual Report, ix, page 66. 



Meg. A fine or medium-grained diabase, somewhat altered and containing much 

 red, feldspathic material. 

 No section. 



Age. Cabotian(?) u. s. o. 



No. 279. DIABASE. 



Prom a dike west end of Governor's (or Susie) island. 

 Ref. Annual Report, ix, page 66. 



An ordinary gray, rather fresh diabase, in which, in thin section, an ophitic 

 structure is evident, and in which is a very small amount of olivine. 



Age. Cabotian(?) N. H. w. 



No. 280. DIABASE. ( Porphyritic. } 



"Rock like No. 269, and in its bearing. Forms the north point that encloses the long bay on the east end 

 of Governor's (or Susie) island, cutting the quartzitic slates that dip south on each side." S. E. } S. E. % sec. 

 32, T. 64-7 E. 



Ref. Annual Report, ix, pages 66, 67. 



Meg. A fine-grained, dark-gray diabase with some red material. A few por- 

 phyritic plagioclases are present. 



Mic. The section shows a considerably altered diabase, quite similar to No. 269. 



One section. 



Age. Cabotian(?) u. s. G. 



No. 281. BORNITE (and vein matter). 



About half a mile from the east end of Governor's (or Susie) island. From a vein which runs north and 

 south. This vein has since been extensively exploited, but without finding copper or silver in paying quantities 

 (see Nos. 1851, etc.) The vein is about three feet wide and is probably in continuation from one of the veins of 

 the mainland of Pigeon point. There are several other such veins in the vicinity. 



Ref. Annual Report, ix, page 67. 



N. H. W. 



No. 282. DIABASE. (Altered.) 



From the main dike of the north part of Governor's (or Susie) island. 



Ref. Annual Report, ix, page 67; Annual Report, x, page 142; American Association for the Advancement 

 of Science, vol. xxx, page 165. 



Mic. This is a diabase in which the augite has become changed to chlorite and 

 hornblende. Otherwise it is similar to several others already described, but has an 

 occasional feldspar of an earlier consolidation. 



One section. 



Age. Cabotian(?) N. H. w. 



