JR. Chalmers — Pre- Glacial Decay of Hocks. 279 



in the maritime provinces of New Brunswick, Nova Scotia and 

 Prince Edward Island upon areas occupied by Carboniferous 

 rocks, and have subsequently been observed in almost every 

 part both of the higher and lower grounds. In the numerous 

 localities where they were seen the superposition of the 

 bowlder-clay was a constant feature, except in the Magdalen 

 Islands, where the products of glacier action seemed to be 

 absent. In the great Carboniferous plain the general charac- 

 ter and condition of these beds are closely similar through- 

 out and are such as to indicate that, in pre-Pleistocene 

 time, a thick continuous sheet existed. They are much thicker 

 and of greater bulk in Prince Edward Island, however, than on 

 the mainland, in many places exceeding the bowlder-clay beds 

 in volume. In the central part of the island along the railway 

 line, where they seem to have suffered less denudation than on 

 the coast, beds of sedentary material, five, ten and even twenty 

 feet in thickness were observed. In many places they are 

 capped only by stratified or partially stratified gravel, sand, and 

 clay of variable thickness, due to fluviatile, marine, or perhaps 

 ordinary atmospheric action, though usually bowlder-clay 

 overlies them throughout the island. On the mainland of New 

 Brunswick and Nova Scotia, especially near the coast, the 

 decomposed materials were seldom seen in situ of greater 

 thickness than about five feet, and often not exceeding a foot 

 or two. A section at one of the numerous localities in which 

 these products occur in the Carboniferous area of New Bruns- 

 wick, seen along the highway between Chatham and Richi- 

 bucto near the Black River bridge, is as follows : (1) Gravel 

 and sand, unstratified, containing fiat, angular fragments of rock 

 apparently in situ imbedded therein, thickness, eighteen inches ; 

 (2) rotten rock, with loose pieces of the underlying sandstones 

 also in place, but with a little gravel and sand in the interstices, 

 four to five feet ; (3) gray sandstone showing still less decom- 

 position, and evidently passing into the solid rocks (millstone 

 grit) beneath, which here lie nearly horizontal. 



Wherever the unabraded or non-glaciated rock surface beneath 

 the decayed rock is exposed, it usually presents a mammillated 

 appearance, showing that the corroding action has penetrated 

 more deeply in some spots than in others. No foreign bowld- 

 ers or other drift materials occur in these beds, though they 

 are not uncommon in the overlying bowlder-clay and upon the 

 surface. 



In southern New Brunswick and in some parts of northwest- 

 ern Nova Scotia the character of the decomposed beds is differ- 

 ent from that of those met with upon the Carboniferous areas, 

 being dependent upon, and of course closely related to, the 

 underlying rocks there. On the pre-Cambrian the materials 



