1 858.] beneath the South- Eastern parts of England, 513 



gist, have doubtless argued that Blackheath, with its rounded 

 shingle, must at some time or other have been at the sea-side. 

 Assemblages of marine shells are the evidences of former seas ; 

 land and fresh-water shells and plants of old lakes and terrestrial 

 conditions. 



By the aid of such guides as these, the form of the area of the 

 coal measures may be defined. Commencing in the west, we have 

 early indications of the proximity of dry land and fresh-water accu- 

 mulations. The earliest carboniferous deposits contain fern-like 

 plants in wonderful profusion and beauty : with them are *' pond 

 muscles " (anodon). The land here lay to the south. The deposi- 

 tions of the North of Ireland require the existence of a wide expanse 

 of dry land somewhere beyond it on the north. The Wicklow moun- 

 tains were part of the dry land of the coal period. In the beds of 

 the carboniferous limestone near Dublin may be seen angular frag- 

 ments of the peculiar granite of these mountains, and which must 

 have been floated away by seaweeds from a shore line, just as hap- 

 pens now. Dry land connected the Wicklow mountains with those 

 of Wales. If we pass over this interval we find evidence that the 

 mountains of Wales were then dry land. The conditions of por- 

 tions of the coal measures bordering on this region have been investi- 

 gated by most competent geologists, Sir R. Murchison and Mr. Prest- 

 wfch. In the Shrewsbury district are pure fresh-water limestones. 

 Coal brook-dale, throughout the whole accumulation of its beds, 

 seems to have been immediately subordinate to an area of dry land. 

 The great Yorkshire coal series, which has been so well described 

 by Professor Phillips, is wholly lacustrine, with the exception of 

 one intercalated band of marine limestone. 



The proximity of dry land to the Edinburgh coal-field has been 

 shown by the researches of Dr. Hilbert and Mr. L. Horner, in the 

 fresh-water deposits of Burdie. The mountains of Cumberland 

 were dry land, and so all those of the border counties which range 

 from Wigtonshire to Berwick. All the mountains of the western 

 highlands of Scotland, an area extending north beyond the Shet- 

 lands, and westwards into the Atlantic, was also land surface : a 

 vast tract lay in this (the north) direction, of which the great 

 Scandinavian chain alone remains, and which supported the rivers 

 which bore down the waste of granitic and crystalline rocks which 

 enter so largely into the coal-measure sandstones of our northern 

 districts. 



Passing across into the Cotentin, we find a series of coal forma- 

 tion, skirting the old mountain ranges of the north-west of France. 



The great central granitic plateau of France is fringed with 

 coal growths, and over the whole of its surface, are innumerable 

 small coal-fields, the lacustrine accumulations of the valleys of that 

 region — this was an upland coal region. 



The "Vosges mountains have been raised over a surface which 

 was dry land, and was connected with the Schwartzwald, the 



