194 REPORT— 1873. 



ridge to the place it now occupies, had the actual heights been the same as 

 now and the climate as cold as that of Canada at present, wiU be ob- 

 vious to every one conversant with that country. It is only necessary to 

 suppose that the block fell from a cliff into a stream where the water was at 

 least sometimes of sufficient depth that when frozen round the mass the latter 

 would be lifted by the buoyancy of the ice. On the breaking up of the ice 

 the floods would transport the rock so long and so far as its ice-buoy was 

 capable of supporting it ; and though the distance accomplished in a single 

 journey might, and probably would, be inconsiderable, by a repetition of the 

 process season after season it would become equal to any assigned amount. 

 Blocks of great size have been in this way transported in Canadian rivers for 

 100 miles or more. Again, were Lundy Island capable of generating a 

 glacier and launching it into the sea as an iceberg, there would be no diffi- 

 culty in supposing that any number of boulders might be transported thence 

 to the mainland of Devon. 



In short, whether the boulder came from Dartmoor or Lundy or any more 

 distant source, it must have been transported by ice-action ; and hence its 

 presence where it now lies is good evidence of a cUmate in this country much 

 colder than that which at present obtains. 



From the foregoing considerations it will be seen that, if the mass were 

 ice-borne, the land could not have been higher above the sea during the era 

 of the boulder than it is at present. There is nothing, however, to prevent 

 its being lower. The boulder may have been dropped by an iceberg on or 

 near the spot it now occiipies when that spot was covered with deep water. 

 The only stipulation to be made on this point is, that the land which 

 fuirnished the mass was capable of supplying it with an ice-body. 

 For example, if the boulder was derived from Dartmoor, Devonshire as a 

 whole could not have been any thing like 2050ft. lower than at present; for 

 that would have been to submerge the entire country, whereas there must 

 have been subacrial land sufficient to form the ice-raft whose buoyancy 

 floated the boulder. 



It is hoped that the steps proposed to be taken by the Committee will 

 enable the boulders of one or two districts at least to be systematically 

 mapped, and the existence of other such remarkable boulders as the granite 

 boulder on the shore of Barnstaple Bay to be recorded. Any attempt at 

 systematic classification, however, must necessarily be deferred until the facts 

 are more largely accumulated. 



Fourth Report on Earthquakes in Scotland, drawn up by Dr. Bryce, 

 ■F.G.S. The Committee consists of Dr. Bryce, F.G.S., Sir W. 

 Thomson, F.R.S., Geo. Forbes, F.R.S.E., and Mr. J. Brough. 



The conjecture hazarded in last Report, that " the state of quiescence " 

 therein referred to was " not likely to continue," received a speedy fulfil- 

 ment. In a postscript to the Report, which was not, however, forwarded 

 in time to be read at the Meeting, it was noticed that " while the Associ- 

 ation was in Session at Brighton an earthquake of considerable severity " had 

 " occurred in the Comrie district ;" and in April of the present year another 



