PETROGRAPHIC GEOLOGY AND DESCRIPTIONS. 779 



Esterelly te. Porphyry . ] 



No. 1767. ESTERELLYTE (inclusions in). 



Corner of sec. 29, T. 65-6, Kekequabic lake, on the porphyritic knob. (Compare Nos. 1094, 1398, 1400.) 

 Ref. Annual Report, xxi, page 159. 



Meg. Pebbles from the porphyry. 



Mic. Three slides were made from these pebbles, viz.: 



1. Granitic esterellyte. In this slide the rock differs from the normal condition 

 of the porphyry (Nos. 1062 and 1095) in having very little of the fine groundmass 



surrounding the larger crystals. One portion is, how- 

 ever, distinctly micro-granulitic, and in that fact the 

 pebble is allied to the normal porphyry. The augite, 

 so-called, has a negative elongation, n f being nearer 

 the vertical axis, with which it makes an angle of 27, 

 as in the accompanying diagram. Dr. Grant shows 

 that it may be 22 (Twenty-first Annual Report, page 

 46). This character shows that the augite approaches 

 aegyrine.* 



FIG. 46. .#:GYRINE- AUGITE IN NO. 1767. OT Ji'ij: u-ui JM. 



2. Is composed entirely ot ampnibole, often show- 

 ing a zoned enlargement, and also often in fine fibres placed at random in the slide. 

 As inclusions the larger crystals contain much magnetite in fine powder and as small 

 crystals. 



3. Is so fine that it cannot be described exactly, but with a little feldspar it 

 consists largely of some amphibole, and hence is allied to No. 2. Three sections. 



Age. Archean (Keewatin). 



Remark. These inclusions might all be styled dioryte, or No. 3 perhaps more 

 correctly amphibolijte. They were collected with others, of which no sections 

 were made, as pebbles in a supposed conglomerate. If, however, the rock in which 

 they lie be considered an igneous rock they should rather be called inclusions. Such 

 pebbly forms are distributed throughout this knob of porphyry, but are most numer- 

 ous on the northeastern slope. They all appear to have been caused to approach the 

 characters of the rock in which they he. N. H. w. 



No. 1768. PORPHYRY. (Pebbly.) 



From the same porphyry knob at the northeast extension. 

 Ref. Annual Report, xxi, page 159. 



Meg. Not porphyritic, fine grained, not evidently fragmental, graduates into 

 the porphyritic portion. 



Mic. One section made is "porphyritic," like the rock of the knob, having frag- 

 ments of crystals of the usual much twinned feldspar and oiiryi/rine, in a finer ground- 



* Minh'alvyle de France, vol. 1, p. 5ti8. 



