﻿Archdeacon Pratt on the Solid Crust of the Earth. 307 



strata, and which produced the discordances of stratification between 

 the newer Palaeozoic and Mesozoic formations, were shown to have 

 acted along lines ranging approximately north and south, parallel to 

 the axis of the Pennine Chain, and consequently in a direction trans- 

 verse to those of the previous period. These disturbances were also 

 accompanied by the denudation of strata from the anticlinal arches, 

 and the consequent disseverance of the Coal-measure tracts over 

 certain definite areas. The results of these movements (the second 

 phase in defining the bounds of the coal-fields) were illustrated 

 by Map No. 3. 



From a consideration of the foregoing observations, the author 

 came to the conclusion that the tendency of the British coal-fields to 

 arrange themselves into the form of "basins" (sometimes partially 

 concealed by newer strata), a tendency strongly insisted on by Prof. 

 Ramsay, was due to the intersection of the two systems of flex- 

 ures above described, one anterior to the Permian period, the other 

 anterior to the Triassic period, and that the actual disseverance of the 

 coal-fields into basins was due to denudation acting with greatest 

 effect along the anticlinal arches of these flexures. 



The inference that the Yorkshire and Durham coal-fields are 

 really basins rising to the eastward under the Mesozoic strata was 

 drawn, an inference supported by the easterly rise of the Coal- 

 measures along the sea-coast from the Coquet to the Tyne. 



Guided by these principles, the author maintained that we are 

 now in a position to determine with great accuracy the actual limits 

 of the Coal-measures under the Mesozoic formations over the area to 

 the north of the central barrier ridge (as indicated on Map No. 3), 

 and that to the south of the ridge the application of the same prin- 

 ciples would assist towards the solution of the question, though in 

 a less degree, owing to the fewer opportunities for observation of the 

 Palaeozoic formations. 



The author, however, concurred in the views advanced by Sir 

 R. I. Murchison*, that, in consequence of the great amount of denu- 

 dation which the Carboniferous rocks had undergone over the area 

 of the south of England previous to the deposition of the Mesozoic 

 formations, little coal was to be expected to remain under the Creta- 

 ceous rocks. 



" On the Constitution of the Solid Crust of the Earth." By the 

 Ven. John Henry Pratt, Archdeacon of Calcutta, M.A., F.R.S. 



In this paper the author applies the data furnished by the pen- 

 dulum-observations recently made in India to test the truth of the 

 following hypothesis regarding the Constitution of the Earth's Crust, 

 which he propounded in 1864, viz.: — that the variety we see in the 

 elevation and depression of the earth's surface in mountains and plains 

 and ocean-beds has arisen from the mass having contracted unequally 



* In his Address at the Meeting of the British Association at Nottingham, 

 1866. On the other hand, the views of Mr. R. Godwin-Austen, which tend 

 rather in an opposite direction, should be well weighed by all who are inter- 

 ested in this question. (Quart. Journ. Greol. Soc. vol. xii.) 



