m THE NETGHBOUKHOOD OP SUDBURY, CANADA. 33 



great. The zone over which rock of this character is exposed in 

 some cutting's is not wide, — less than a mile, for at that distance 

 outcrops of a rock distinctly fragmental are exposed. This may be 

 described as a dark quartzite, at times rather flaggy, having a filmy 

 greenish mineral, like a varnish, developed on the divisional planes. 

 In parts the clastic structure is very distinct, the fragments from 

 •25" downwards usually very slightly projecting on weathered sur- 

 faces, but there are occasional larger fragments of a grey granitoid 

 rock up to about 2" in diameter, subangular in form, liock of this 

 character, varying from the finer to the coarser varieties, continues 

 for about ten miles till we reach the clearing where stands the 

 village and railway junction of Sudbury. 



Beyond Sudbury a dark quartzose rock, something like that seen 

 on the opposite side of the village, but even more compact and 

 schistose, occurs in the first cuttings. Then the rock assumes a 

 rather streaky or porphyritic aspect, but on weathered surfaces is 

 seen to contain small fragments less than '5" in diameter, the 

 ground-mass being occasionally slightly schistose. There is a con- 

 siderable thickness of this rock, my specimens being labelled " about 

 J mile from Sudbury." After a time the rock becomes more coarsely 

 fragmental (about | mile from Sudbury), the fragments now show- 

 ing very distinctly on a weathered surface, by a slight bleaching, 

 some looking rather like a felsite, others more like a hole cry stalKne 

 (? gneissose) rock; they are often from 1" to 2" in diameter, some- 

 times larger. Next (about 1 mile) comes a coarse breccia, looking 

 rather like an agglomerate, the fragments often 8" or 12" in diameter; 

 these are of a compact felsitic rock, containing ill-developed elongated 

 prisms, about -5" long, very dark green in colour, like badly crystal- 

 lized hornblende, the matrix in all the cases being apparently a 

 more or less fine-grained quartzite, sometimes rather schistose. 

 Quartzite without fragments now succeeds for a time. Then comes 

 (about 1| mile) another group of fragmental rocks (the matrix being 

 crowded with subangular fragments) ; these are a slightly reddish- 

 grey rock, resembling a microgranulite with dark green spots, 

 gneissose and schistose rocks, and a greenstone or possibly chlorite- 

 schist. The matrix occasionally had an ashy, sandy look, reminding 

 me of some of the so-called quartzites of Blackbrook, Charnwood; 

 sometimes it was the usual quartzose rock. JN'ear the point where 

 we turned back, about If mile from Sudbury, the fragments (this 

 being apparently low in the series) were of smaller size in rather 

 regular layers, the stratified arrangement being very conspicuous on 

 weathered surfaces, where the fragments were bleached. The dip 

 was generally throughout at a moderate angle, say 10° to 20°, roughly 

 to the S.E. I was informed that this is the usual dip of the whole 

 region, the observations varying from E.S.E. to S.S.E. * 



* Possibly the rocks noticed in this paragraph may belong to the (lower) "slate 

 conglomerate " of Logan's section, p, 56 ; but if the Limestone be thin or wanting 

 here, the npper conglomerate also may be present: still, according to the clip, we 

 were descending in the series ; and I feel very uncertain about the correlation of 

 these beds with the less altered conglomerates nearer Lake Huron, specimens 

 from which are mentioned later. 



Q. J. G. S. No. 173. D 



