1867.] ilAW TERTIARY WHITE CLAYS. 387 



ft. in. 



Park Schist 8i 



Main Coal-seam 8 



Grey Schist full of yegetable impressions 1 4 



Coal, very good 1 2 



"Warren earth 11 



making 10 feet 3 inches of Coal of good quality, the main seam being 

 extremely hard and, like Cannel Coal, igniting readily ; it is also of 

 great heat-prodaciiig capacity, but leaves more ash than the best 

 English coals. 



An analysis of samples from two seams, made by Professor Thomas 

 Richardson in London, exhibited the following results : — 



Sample K'o. 1. No. 2. 



Fixed Carbon 37-67 35-42 



Gaseous matter 18-33 21-10 



Ash 44-00 43-48 



The calorific power as follows :- 



jS'o. 1. Xo. 2. 



9-07 8-82. 



These figures give the number of pounds of water which 1 lb. of 

 coal can evaporate from the boiling-point. The best English steam- 

 coals evaporate as much as 12-50 lbs. 



To the immediate fruition of so valuable a property the present 

 obstacle is the want of means of transport, which by survey has been 

 ascertained to be obtainable by a tramway of thirty-seven miles from 

 the centre of the Coal-field to a navigable part of the river Tubarao, 

 where ships of 600 tons burden might take cargoes. 



13. On the SoTTRCES of the Materials composing the White Clays of 

 the Lower Tertiaries. By George Maw, Esq., E.G.S., E.L.S., &c. 



Is" examining some light- coloured deposits that occur between the 

 Boulder-clay drift and the Carboniferous Limestone of Xorth "Wales, 

 an account of which has recently appeared in the Geological Maga- 

 zine*, I was led to the conclusion that some of the beds of very white 

 and pure clays occurring in " pockets " in the Kmestone could not 

 have been derived from the mere mechanical degradation of any 

 previously existing materials ; and an analysis showed that they con- 

 sist of silica and alumina in nearly similar proportions to the silica 

 and alumina in the limestone, and, therefore, that they were pro- 

 bably left behind after its calcareous matter had been removed by 

 watery dissolution. 



The Tertiary formations of Hampshire, Dorsetshire, the Isle of 

 Wight and Devonshire, contain vast deposits of similar white clays ; 

 and I beg to lay before the ISociety a few facts bearing on the proba- 

 bility of their having had an analogous origin by the dissolution 

 of the calcareous portion of the chalk. 



* Vol. iv. pp. 241 and 299. 



