516 J. A. DRESSER IGNEOUS ROCKS OF EASTERN QUEBEC 



connected with the intrusions off Mc Goons point, already mentioned, 

 from Camptonites and allied dike rocks. 



Between Eoxton, in the county of Shefford, and Saint Nicholas, in 

 the county of Lotbiniere, a distance of more than 100 miles, there are 

 several occurrences of intrusive rock in lower Paleozoic strata. It is 

 little known except in connection with copper deposits in the region, 

 which it seems invariably to accompany. It is found at Eoxton, Acton, 

 Upton, Durham, Wickham, Drummondville, Nelson, Saint Flavien, Saint 

 Apollinaire, and Saint Nicholas, and seems to form a series of dikes in a 

 comparatively narrow belt throughout this distance. The dikes vary in 

 width from a few inches to a thousand feet, or even more, and run parallel 

 to the length of the belt in which they occur — that is, in a northeast- 

 southwesterly direction. 



At Eoxton there is an intrusive, a light colored rock of the trachyte 

 class, but in most of its occurrences the intrusive is a diabase, and is com- 

 monly amygdaloidal. 



The largest exposures are at Saint Flavien, Nelson, and Drummond- 

 ville. At Saint Flavien the intrusion is nearly a quarter of a mile wide, 

 and appears to be a wide dike, extending for a distance of about a mile 

 through the country. Similar rock appears at Saint Apollinaire, 7 miles 

 distant. 



These are the principal rock exposures. It is a level district, covered 

 with a heavy mantle of drift. The rock is amygdaloidal in many parts, 

 the amygydules being most commonly filled with calcite; but sometimes 

 epidote and chlorite or quartz form the filling material. Copper fre- 

 quently occurs in this rock, as at Eoxton, Nelson, and Wendover, near 

 Drummondville. In other places, as at Acton, Upton, and "Wickham, 

 the copper occurs in the ektomorphic contact zone of the inclosing rock. 

 The exposure at Nelson is smaller than that at Saint Flavien, while that 

 at Drummondville is apparently quite as large. 



It is thus described by Logan:* 



The greenish sandstones on the Saint Francis are intersected by several 

 dikes of diorite, the courses of which are in a general way down the stream. 

 The rock of the fall at Drummondville appears also to be a diorite and is of a 

 gray or greenish color ; it probably belongs to the stratification and is not 

 known to have any connection with the dikes. It has a breadth of about half a 

 mile, and some parts are porphyritic from the presence of small crystals of 

 light, greenish fieldspar, while others are amygdaloidal, holding small portions 

 of a light and calcspar and occasional nodules of agate. Much of it bears the 

 aspect of breccia, in which fragments of the diorite are held together by a close 

 grained but highly crystalline calcareous cement, approaching in color the 



* Geology of Canada, 1863, p. 243. 



