722 kei'ort— 1884. 



covered with a mantle of decomposed rock, then the ice would not require to exert 

 any very extraordinary power in order to scoop out any number of lake basins, 

 and to leave enormous — apparently water-worn — boulders scattered over the face 

 of the country as we now find them. 



' In Brazd these, what may be called, u boulders of decomposition," with their 

 surrounding decomposed matrix, were mistaken by Agassiz for glacial boulder 

 drift. Their true value, however, having been subsequently pointed out by 

 Professor Hartt, I examined some of these supposed glacial drifts in 1869, and from 

 personal observation can endorse Professor Hartt's view of their nature.' 



The letter above quoted seemed at that time — 1876 — to close the discussion ; 

 nor, so far as I am aware, has the theory I then advanced in explanation of the 

 origin of these rock basins been since alluded to by any one. Therefore I thought 

 it was not inappropriate or without interest, on this occasion, and surrounded as we 

 are by a vast region of such lakes and lakelets, to agrain refer to the subject. 



I have now nothing to add to the facts stated in my letter written eight years 

 ago. I have, however, since then had considerable opportunities for studying the 

 lakes of our great Laurentian region, as well as the action of winter ice around 

 our coasts, and I am more than ever convinced of the inadequacy of ice, however 

 thick, to scoop out solid hard rocks, or to produce the phenomena of lakes and 

 boulders which our great northern glaciated regions now present. "While if the 

 explanation I have advanced is admitted, and as yet I have heard no objection to 

 it, all difficulty seems to disappear. 



•G. On Points of Dissimilarity and Resemblance between Acadian and Scottish 

 Glacial Beds. By Ralph Richardson, F.E.S.E. 



Mr. Richardson said that, in his ' Acadian Geology,' Principal Dawson gave the 

 following as a typical section of the superficial geology of Acadia — that is, Nova 

 Scotia, New Brunswick, and Prince Edward Island — and as, in some respects, also 

 applicable to Canada and Maine, viz. : At the bottom, peaty deposits ; then unstra- 

 tified boulder-clay; then stratified Leda-clay, indicating deep water ; and, lastly, 

 gravel and sand-beds, the Saxicava-sand indicating shallow water. Mr. Richardson 

 pointed out wherein such a section differed from and resembled the glacial beds of 

 Scotland. lie said the latter showed no such orderly arrangement as the Acadian, 

 and could not, as a rule, be divided into deep and shallow waterbeds. The marine 

 shells in the Scottish beds are all mixed up together, regardless, as a rule, of the 

 province — whether Arctic or Brit ish , or both — to which they properly belong ; regard- 

 less of the depths which they usually tenant, and regardless of the deposit (whether 

 clay, gravel, or sand) in which they are now found fossil. They are likewise met 

 with at all heights, from the level of the sea to more than 500 feet above it. No 

 system of dispersion of boulder-erratics from definite centres in Scotland seems as 

 yet ascertained. The peaty deposits occurring in Principal Dawson's section beloio 

 the boulder-clay or till, occur in Scotland above it. With regard to points of 

 resemblance, the facies of the shells in Acadia and Scotland is similar, being of the 

 Arctic and Brit ish- Arctic type. Again, both in Acadia and Scotland, all the shelly 

 glacial beds occur above the unstratitied boulder-clay or till. Mi. Richardson cited 

 various Scottish sections to prove this, and remarked that the belief in earlier and 

 later boulder-clays is of long standing iu Scotland. He concluded by pointing out 

 that, in their cardinal features, the Acadian and Scottish glacial beds seemed to 

 coincide. Iu both Acadia and Scotland that great mass of unstratitied clay known 

 as till existed ; and, doubtless, the geologists of the New "World were, like those 

 of the Old, puzzled to account for its origin with certainty and satisfaction. The 

 question was left unsolved by the meeting of the British Association in Edinburgh 

 in 1850, although then discussed by Hugh Miller and Professor John Fleming. 

 The author hoped that during the present meeting some advance would be made 

 in solving this great problem, as well as in correlating and arranging the glacial 

 beds of Canada, Acadia, and Britain. 



