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APPENDIX. 



Charnwood Forest hills, the sienitic greenstone of Warwickshire, the 

 transition rocl^s of Dudley, the Malvern Hills, and the trap rocks of 

 Gloucestershire, Somersetshire, and Devonshire, were probably parts 

 of one range, and were much loftier than at present. It may deserve 

 notice, that the granitic rocks, in this range, are closely allied to rocks 

 now generally supposed to be of igneous origin. 



It was this range that appears to have determined the extent of our 

 island in that direction, and to have formed the western border of an 

 ancient sea or lake, in which the upper calcareous strata of the mid- 

 land, eastern, and southern counties w^ere deposited. It also appears 

 to have determined the extent of the upper calcareous strata, that 

 cover the eastern side of England, and are bounded by the line a a a. 

 This boundary marks the direction of a range of calcareous hills, that 

 extends through England in a waving line, from the western extremity 

 of Dorsetshire, to the eastern side of the county of Durham. East of 

 this line, there are no beds of good mineral coal in any part of Eng- 

 land. Between the line a a a and the Alpine districts (coloured red), 

 we have the under secondary strata (coloured green.) All the prin- 

 cipal coal formations in England occur in different parts of this dis- 

 trict, which, for the sake of distinction, we shall call the middle dis- 

 trict : it is however partly covered by beds of red marl and sandstone. 

 The upper calcareous district^ east of the line a a a (and coloured 

 yellow in the map), is in some parts covered with beds of clay and 

 sand of a more recent formation, belonging to the tertiary strata : 

 they are coloured brown, and are bounded in the map by the lines 



0 o o o. Other low parts of this district are covered by alluvial dep- 

 ositions, and marked 111. 



England and Wales may thus be divided into three geological dis- 

 tricts : — the Alpine district, consisting of primary and transition 

 rocks, — the Middle district, comprising the coal formation and the 

 lower secondary strata of new red sandstone, — and the Upper Calca- 

 reous district, comprising the lias, the oolite and chalk formations ; 

 the latter partly covered by tertiary formations. Each of these dis- 

 tricts has its appropriate characters and mineral productions. In or- 

 der to give the reader a clear idea of the relative position of the rocks 

 and strata of these three divisions, let him take three sheets of paper, 

 and cut out the form of England in each. Let the lower sheet be red ; 

 cover this with green paper, cutting out all the parts on the western 

 side, which will leave the parts marked red in the map uncovered, 

 and also the small parts where the Malvern Hills and Charnwood 

 Forest hills are situated. Cut out the third sheet of yellow paper, so 

 that its edge may correspond with the line a a a. Then cut out pieces 

 of darker-coloured paper, and place them over the parts marked 2 2 2, 

 for the tertiary strata ; and place dark patches on the parts marked 



1 1 1, for alluvial and diluvial depositions ; raise the w^estern edge a 

 little, so as to make the sheets of paper incline to the south-east ; — 

 and we shall then have a model of the geology of England, which 

 would be more complete, provided we could raise the parts marked 

 red above the level of the green paper. The red paper, which 

 spreads under the whole, and represents the primary and transition 

 rocks of the Alpine districts, may be conceived to extend under the 



