80 PALEOZOIC TIME. [CHAP. VI. 



accordingly those two rocks were never deposited upon 

 it." l 



On the north-east side of the Leicestershire coalfield the 

 Millstone Grit and Carboniferous Limestone are again 

 found ; and south-eastward, near Northampton, the Lime- 

 stone was found in one deep boring, and Lower Carboni- 

 ferous shales and sandstones in another ; but at Orton 

 (twelve miles to the north-east) a thin representative of the 

 Trias rests directly on a quartz-felsite resembling some of 

 the Charnwood rocks. 



Whether the land we have traced terminated in Leicester- 

 shire, or widened out again eastward and formed part of 

 a larger land mass in that direction, there is at present no 

 evidence which will enable us to decide; but, as it 

 evidently became very narrow in Leicestershire, we have 

 thought it safer to show land on the map only so far as 

 there is evidence for it, and therefore to suppose that it 

 was surrounded by the sea in Lower Carboniferous times. 



We have now to consider whether any other tracts are 

 likely to have existed as islands at this time, and the first 

 tract that claims attention is that known as the Lake Dis- 

 trict. That this was an island at the commencement of 

 the Limestone epoch is tolerably certain, as testified by the 

 conglomerates and sandstones which form the base of the 

 Limestone series ; but the question How long did it re- 

 main unsubmerged ? is a very difficult one to answer. " It 

 has been discussed by the Eev. J. C. Ward, 2 who comes to 

 the conclusion that only a very small area north of the 

 Keswick Valley could have been above water, since the 

 Mell Fell conglomerate runs up to a height of 1,760 feet. 

 Curiously enough, this conglomerate consists chiefly of 

 Upper Silurian detritus, and not of stones derived from 

 the Ordovician rocks against which it rests. Mr. Ward 



1 " Geology of the South Staff. Coalfield," first edition, p. 253. 



2 " Geol. Mag,," Dec. 2, vol. vi. (1879), p. 58. 



