96 THE CANADIAN NATURALIST. [^pril, 



following are the most important differences between this and pre- 

 ceding maps : 



1st. Upon Dr. Robb's map the whole course of the Tobique, 

 with the exception of the Red Sandstone District, is colored as if 

 passing through Upper Silurian rocks. In reality most of the 

 country between the Blue Mountain Brook and the Forks is of 

 a trappean character. 



2nd. The calciferous slates of the Narrows are separated from 

 the Red Sandstone district by ferruginou? slates and dark sandstone. 

 The calciferous slates and the sandstones have a northeasterly 

 strike, and similar rocks are again seen above the Forks, with the 

 same strike. They are probably continuous. 



3rd. The exact limits of the Red Sandstone District, on the line 

 of the river, are the Red Rapids and the Blue Mountains, 



4th. The Blue Mountain and Bald Mountain rise directly 

 from the waters of the lake or river, not at the distance of several 

 miles, as represented on other maps. 



5th. On the map of Dr. Robb no distinction is made between 

 trappean, syenitic, and feldspathic rocks. In the accompanying 

 map, the Blue Mountains, which are trappean, are distinguished 

 from the Bald Mountain and Nepisiquit ranges, which are chiefly 

 feldspathic. There is an island of slate in Nictau Lake. 



6th. The uppar half of the Nepisiquit, on Dr. Robb's map, is 

 marked as running through upper Silurian strata. On the contrary 

 the whole district, colored yellow on my map, is feldspathic, con- 

 sisting partly of granulite and partly of syenite, more particularly 

 the former. Rocks of this character, forming lofty mountain ranges, 

 cross the stream in a northeasterly direction, and are seen nearly 

 as far as the Indian Falls. At the latter place highly altered rocks . 

 cross the stream, with a strike 10^ west of north. 



7th. The granit. band which has been supposed to cross the 

 Province from the Chepatnecticook Lakes, and which on Dr. 

 Robb's map has tLe same width at the Nepisiquit which it exhibits 

 elsewhere, really nan ows in the vicinity of that stream to a very 

 small strip, and probably soon disappears. Owing to the tortuosi- 

 ties of the river, these rocks appiar at several successive points, 

 and at first would lead one to believe in the existence of several 

 granitic anticlinal axes. From the fact however that all the slates 

 seen above the Pabineau have a westward dip, it is probable that 

 only one band is successively exposed. Where this band finally 



