133 Correspotidence — Daniel Jones. 



currents which, iu conjunction with the disintegrating power of 

 frost and the oscillations, of the northern land, has been operating 

 since the dawn of geological time in the great and continuous trans- 

 ference of sediment from the arctic towards the temperate and 

 tropical regions, and which has been so largely instrumental in 

 building up the successive formations of our continents, and has been 

 equally efficient iu the distribution of the materials of Post-pliocene 

 clays and gravels, and of the sand-stones and conglomerates that 

 make up Palseozoic mountains. 



With reference to the erosive power of the modern Arctic currents 

 I may state that my inferences from the materials obtained by sound- 

 ings on the American banks, have been confirmed by the recent 

 dredgings undertaken under the auspices of the United States 

 Government, as reported by Prof. Verrill in Sillimans Journal ad- 

 vance sheets of February number). With reference to the St. 

 George's Bank, for example, he says that the bottom on the edge of 

 the bank is composed of sand or gravel and broken shells, and that 

 the former, while boreal, is identical with that found in the Bay of 

 Fundy, in regions swept by strong currents. 



Perhaps I should add that I by no means deny the existence of 

 local glaciers in the hills of Eastern America in the Post-pliocene 

 period ; but I find no evidence of a continental glacier covering the 

 plains. J- W. Dawson. 



McGiLL College, January, 1873. 



FOREST OF WYRB COAL-FIELD. 

 giR^ — ^In a paper on the Correlation of the Carboniferous deposits 

 of Cornbrook, Brown Clee, and Coalbrookdale, published in the 

 Geological Magazine, Vol. VIII. No. 8, Aug., 1871, I endeaA'oured 

 to show that at Harcott, near Kinlet, there was a patch of the older 

 coal-measures containing workable and good coals allied to the lower 

 beds of the Coalbrookdale coal-field, underlying the Upper Coal- 

 measures of that part of the Forest of Wyre coal-field. The extent 

 of this underlying patch of older coals is a matter of some import- 

 ance in these days of scarce and dear coal. It can only be ascertained 

 by actual proof by sinking or boring, since its boundaries are all 

 covered over by the Upper Coal-measures. I do not expect that it 

 is more than an old island, so to speak, of older coal-measures, as are 

 the coal patches of Brown Clee, Shirlot, and Cornbrook, but it may 

 be an island or patch spared from denudation of many hundred acres 

 in extent, and I have every reason to believe that it extends under 

 the whole of Kinlet Park. I am favoured with a communication 

 from Mr. William Birchley, of Billingsby, from which it appears 

 that he has reached these older coals at about 250 yards east of 

 " The Cape of Good Hope " Inn, Billingsby, at a depth of 160 yards. 

 I expect full details of this section in due time, which I shall be 

 happy to communicate for the benefit of your readers. Mr. Birchley 

 says, " At no great depth we came upon a white rock, very hard, and 

 containing streaks of crystal-like substance, which the sinkers call 

 ' Later.' This rock was about 29 yards thick, and under it clunch 



