﻿122 NEW YORK STATE MUSEUM 



v. I Early Devonic of Eastern North America, 1908). This 50- 

 fathom line is a submarine terrace at this point, one of the steps 

 leading down to the great cut in the Bonaventure rock plateau made 

 by the channel of the St Lawrence river. What is actually ex- 

 hibited in this sketch is the present stage of the attack of the gulf 

 waters on the folded and unfolded rocks of Perce, supplemented by 

 the outstanding fault faces of the mountain cliffs and by the gen- 

 eral effect of weathering denudation. 



A contrast of fundamental moment lies in the attitude of the 

 younger and older rock beds ; the former horizontal or gently un- 

 dulating, the latter simply inclined and, on the south front, vertical. 

 A fact of similar moment is that the latter, consisting of Lower 

 and Upper Siluric and Lower Devonic, are exposed in jutting 

 cliffs by the removal of the mantle of softer beds from over them. 



Bonaventure sands and conglomerates. These beds lie today 

 much as they were originally laid down in the shallow waters of a 

 rough coast which must have been not greatly unlike, in its broken 

 rugged cliffs, the coast of Perce as it is now. I believe the Bona- 

 venture series of beds, at least so far as we can distinguish it from 

 the Gaspe sandstone series, or so far as it can be defined from its 

 original section on Bonaventure Island, represents in time the latest 

 stage of the Devonic and possibly the earliest of the Carbonic. We 

 can not prove the latter affiliation from any evidence around Perce, 

 nor indeed is this age demonstrable from intrinsic evidence at any 

 point throughout its distribution from Gaspe bay to the head of the 

 Bay of Chaleur. We have been in the way of deferring to current 

 opinion in this matter, but can now go no further than to recognize 

 an interval between this deposit and the earlier Devonic of the 

 country, often intensified by down-faulting, the absence of any 

 marine later Devonic and the continuity of this mass of sands and 

 conglomerates as an accumulation of landwash along a bold up- 

 turned Precambric and early Paleozoic coast. I have had occasion 

 before to refer to the fossil-bearing pebbles of this conglomerate, — 

 Cambric, Siluric and Devonic; heads of Halysites often of large 

 size (that here figured is from the cliff face on Bonaventure Island) ; 

 fragments of the Gaspe sandstone and of the Perce Rock massive 

 with their characteristic species. There is some order in the assort- 

 ment of these pebbles, for there are as a rule few jaspers and other 

 crystallines mixed with the limestones and few fossil-bearing blocks 

 where the crystalline pebbles abound. Logan records a block in 

 this conglomerate weighing upward of eight tons, but while such 

 large ones are not familiar to my observation there is plenty of 



