APPENDIX. 679 



(IS.)— Grand Manan. 



This isolated portion of New Brunswick 1ms hitherto been a blank in the 



geological map, and for this reason 1 insert lure a note kindly communi- 

 cated to me by Professor A. E. Vcrrill of New Haven, who, though he 

 visited the island for zoological rather than geological objects, has given 

 some attention to its structure. 



"The stratified rocks of the island appear to represent at least two 

 formations which are unconformable. 



" The one, which is apparently the oldest, occupies the belt of low land 

 and the shore cliffs from Whale Cove and Northern I lead, along the whole 

 eastern side of the island, to Grand Harbour, about the middle of the 

 island, beyond which I have also seen outcrops of it in several places, 

 but have not examined the whole extent. The same rocks compose Long 

 Island, Duck Islands, Rosse's Island, Whitehead Island (in part at least , 

 and nearly all the other small islands off the east side of Grand Manan. 

 Inner "Wood Island is, however, partly composed of conglomerate and fine- 

 grained dark-red sandstone, with an easterly dip, which may belong to a 

 higher formation ; and Gannet Rock, upon which there is a lighthouse, 

 was described to me as composed of conglomerates. The Three Islands, 

 which are the most eastern, are in the main composed of rocks similar to 

 the eastern shore of the main island, but upon the outer one I found also 

 a bed of white crystalline limestone. 



"The series of rocks alluded to are highly altered, much distorted and 

 broken, and cut through by numerous immense dykes and masses of trap, 

 and consist of talcose and clay slates, mostly grayish, but sometimes black, 

 calcareous grits, altered gray sandstones, in one case with vegetable traces, 

 but sometimes so indurated as to become quartzites, or, when impure, ap- 

 proaching a syenitic character. Included in these gray sandstones and slates 

 near Pettee's Cove, there is a bed of black carbonaceous shale, very fissile, 

 as if it ought to yield plant-remains, but I could find none. Included in 

 similar rocks near the same place are several true veins of heavy-spar, 

 mostly massive and pure, but in one case carrying some galena, copper, 

 pyrites, etc. On Rosse's Island, inclosed in black slates, probably of the 

 same age, there are enormous masses of white quartz, conspicuous above 

 the general surface, some of them 100 feet or more across, and from 10 to 

 40 high. The dip of these rocks is so variable and irregular that no 

 general statement can be made. "Where least altered, it was often to the 

 N.N.E. 45°, but at other times they were nearly vertical or even inclined 

 to the S.W., varying in short distances. 



" The second series of rocks occupy the northern end of the island to 

 the west of Whale Cove. Commencing at this Cove and going west, we 

 find first regularly columnar trap for a short distance, and then, apparently 

 resting upon it, thick-bedded, regularly stratified massive rocks of various 

 composition, but mostly amygdaloidal, trap-ash, and compact quartzoze 

 rocks in beds 10 feet or more thick. These occupy the shore for about 

 two miles, forming cliffs from 100 to 200 feet high. They are at times 

 nearly horizontal, in other places dipping to the W. or S.W. about 10° 

 to 20°. The amygdaloidal cavities contain calcites, stilbites, apophyllites. 



