80 BULLETIN OF THE NATURAL HISTORY SOCIETY. 



The general character of the pre-Canibrian volcanics 

 that I have seen is tolerably uniform. They are mostly 

 either feldsparporphyry or diabase, or approach closely 

 to one of these two types. Strongly quartzose porphyries 

 are not common, nor are intermediate rocks of the andesite 

 type, wliile olivine rocks have not been recognized among 

 the eifusives. A soda-granite occurs among the Haronian 

 rocks near Upham, but its relations to them are doubtful. 



The Huronian began in southern 'New Brunswick 

 with rocks exclusively volcanic. These reached in places 

 an enormous thickness (up to 11,000 feet in the Kingston 

 Group at J^ew River), but in places they thin out to a 

 few hundred feet of fine-grained tuff's, or are entirely 

 absent. They are covered by coarse red rocks, conglom- 

 erates and shales, which are thought to have been rapidly 

 deposited over an area of dying volcanic activit}', and have 

 some interbedded volcanic deposits. After this followed 

 a long period of rest while the Cambrian and Ordoviciaii 

 slates were being deposited. In the neighborhood of St. 

 John there was no resumption of volcanic activity, but in 

 the region about Passamaquoddy Bay the Silurian was 

 again a period of igneous outbursts — of lavas and 

 ashes, which now lie interbedded with the fossiliferous. 

 sediments, and form the more prominent liills of that 

 neighborhood. In tlie northern part of the province,, 

 around the upper part of Bale Chaleur, are large areas of 

 volcanic rocks, felsites and traps, which cut through 

 Silurian slates, but appear to be earlier than the Devonian 

 rocks. These eftusives form high hills standing out pro- 

 minently along the shore between Bathurstand Campbell- 

 ton ; at the latter town the Sugarloaf Mountain, rising 

 abruptly over 1,000 feet, is composed of felsite. Smaller 

 areas of volcanic rocks, cut the Silurian slates in other 

 parts of the province ; at Moose Mountain, east of the 



