88 b 



GEOLOGICAL SURVEY OF CANADA. 



Banded 



trachyte. 



Agglomerates, they are associated with rough agglomerates, which, in one instance, 

 were noticed to hold fragments up to four feet in diameter. In some 

 places agates are quite abundant, but these were nowhere observed to 

 be of fine colours, being in general either milky-white or pale grey. 

 With the exception of the agglomerates, which are sometimes consider- 

 ably disturbed, the rocks of the western portion of the first expansion 

 of the Inlet lie at very moderate angles, and are often nearly horizontal 

 or undulating with low dips. 



A mile south of the Ain Eiver, a rather remarkable pale greyish- 

 purple trachytic rock, with partly decomposed felspar crystals 

 porphyritically imbedded, occurs in well marked beds. In several 

 places in the upper expansion similar rocks more acidic in composition 

 than those first described are found, but varying in colour and texture 

 from place to place. Near the head of this part of the inlet, and in a 

 small island south-west of Tas-kai-guns Island, a peculiar laminated 

 felspathic rock was noted, which may occur in many other localities, 

 as it is quite abundant among the pebbles in the drift deposits of the 

 eastern shores of the Inlet. 



The rock is generally grey in colour, and its lamination is evidently 

 the result of movement while in a viscous state. Under the micros- 

 cope, the structure is resolved into a series of closely alternating light 

 and dark felspathic bands. In some places very small segregations of 

 quartz have been formed subsequent to the cooling of the mass. 



A second small islet north-east of Tas-kai-guns is composed in great 

 part of a species of ,pbsidian. The rock is roughly bedded and dijDstwo 

 ways, as though forming a small anticlinal. The greater part of the 

 obsidian is dark grey or black, with a glassy lustre, but very tender, 

 being traversed by innumerable fine cracks, which cause it to fall into 

 prismatic fragments under a light blow. Some small beds are reddish 

 in general colour, a granular material of that tint being intercalated 

 with resinous-looking dark conchoidal-fracturing obsidian in little layers 

 or lenticular masses. The obsidian is finely laminated, and under the 

 microscope is found to be very rich throughout in small microlites. 



The Ma-min Eiver flows into the eastern side of the upper expansion 

 of Masset Inlet, coming from the south-east. Coal was reported to 

 occur on this stream, and supposed possibly to indicate the extension 

 of the Skidegate measures. After some little difficulty, an Indian who 

 knew the locality was found, and my assistant, Mr, E. Dawson, visited 

 it with him. The tide runs up the river about half a mile ; above this 

 there are occasional little rapids, but the country is all flat and low. 

 About one mile and a half below the coal exposure, which is about six 

 miles from the mouth of the river, Tertiary basaltic rocks begin to 

 appear in the stream. The so-called coal proves, however, to be merely 



Obsidian. 



Lignite on Ma 

 ruin Eiver. 



