344 



CHIEF BRITISH CONVULSIONS. 



Geological Period of the 

 - Convulsions. 



During the deposi- 

 tion of the Harlech 

 and Bangor grits . 



. After the Silurian) 

 strata and before' 

 the Carboniferous f 

 system . . .) 



During the Carboni- ) 

 ferous period . \ 

 IL Before the adjacent ( 

 rocks of the Per- 1 

 niian system taken j 

 generally . . ( 



During the Permian ) 

 period . . . ) 



III. After the earlier I 

 Permian period ? . \ 



After the later Per- ) 

 mian period . . \ 



During the Oolitic I 

 period ? . , \ 



IV. After the Oolitic 

 period . 



During the Chalk 



period ? 

 After the Chalk 



period . 



V. After the Eocene 

 deposits 



Effects Noted. 



Production of Conglo- \ 

 merates . . . j 



Porphyry and dolerite J 

 and Trappean Con- > 

 glomerates . . ) 



Disturbed position of I 

 Primary rocks ; vol- < 

 canic outbursts . I 



Production of Old Red ) 

 Conglomerates . C 



Marine bed among es- ) 

 tuary deposits . ^ 



Numerous dislocations,^ 

 fissures of dykes and f 

 veins, anticlinal axes, f 

 &c. . . .) 



Production of Conglo- ) 

 merates . , . 



Veins of lead,&c., Great 1 

 or 9O-fathom dyke . \ 



Production of New ) 

 Red Conglomerates \ 



Unconformity. Kello- \ 

 way rocks in contact I 

 with the Lower Oo- \ 

 lite group, excluding j 

 the upper portion . / 



Unconformity of strata ) 

 between Oolitic and > 

 Chalk systems . \ 



Estuary deposits. Peb- 

 ble beds of Lower 

 Greensand 



Pebble beds, wasted 

 surface of chalk 



Vertical strata . 



Marine deposits be- 

 tween lacustrine beds \ 

 The crag . 



Localities of some of the 

 Phenomena. 



Derwent Water Cum- 

 berland, North Wales. 



Grasmere in Westmore- 

 land, Radnorshire, Me- 

 rioneth, &c. 



The Grampians, Lam- 

 mermuirs, Cumbrian 

 Mountains, North 

 Wales. 



The Highland Border, 

 Cumbria, &c. 



Yorkshire. 



In all Coal Districts of 

 this era, both in Europe 

 and America. Charn- 

 wood, Crossfell fault. 



North of England, north 

 of Germany. 



Yorkshire, Pontefract, 

 Mendip hills, Tyne- 

 mouth castle, border of 

 Cumbrian group (Kirk- 

 by Stephen). 



North of England. 



Cave, Yorkshire. 



Yorkshire wolds, Dorset- 

 shire cliffs. 



Weald of Kent and Sus- 

 sex, Isle of Wight, &c. 



Hertfordshire, Vale of 



Thames. 

 Isle of Wight, Isle of 



Purbeck. 



Isle of Wight. 

 Essex and Norfolk. 



The Roman numerals are applied in the above list to all periods 

 where considerable movements are traced in direct effects of disloca- 

 tion and conformity. 



The next table presents the results of a more extended survey of 

 direct convulsive effects on the continent and islands of Europe, as 

 they appeared to E. de Beaumont on the first proposal of his ingeni- 

 ous views of subterranean movement : 



