35 



Notes upon the Physical Structure of the Watehett are'i, and the 

 relation of the Secondary Rochs to the Devonian series of West 

 Somerset. By Robert Etheridge^ T.Gt.S., F.R.S.E. 



Perhaps no area in Great Britain exhibits so extensive a series 

 of Lower Secondary Rocks, as West Somersetshire and Glou- 

 cestershire, more scattered in the former than the latter, owing 

 to circumstances dependant upon physical structure and local 

 conditions, or expression of eosmatical causes and effects, which 

 to be understood must be seen and carefully examined ; the 

 grandeur of the West Somerset coast and its geological structure 

 as seen between Little Stoke on the east of Quantocks Head, and 

 Greenlay Point west of Minehead in the Bristol Channel, must 

 be examined in detail ere the remotest idea of cause and effect 

 can be appreciated ; the expanse of water occupying the estuary 

 of the Severn (some 14 miles) from the Somerset to the Glamor- 

 ganshire coast, comprises an area once a continuous and great 

 plain of New Red and Lias, surrounding high lands composed 

 of Devonian and Carboniferous Rocks stretching locally from 

 the Mendips on the north-east to Exmoor and Dartmoor on the 

 west and south-west, with the south flanks of the South Wales 

 coal basin and the Old Red Sandstone of Monmouthshire as its 

 northern frontier. The vast alluvial flats of Somerset east of 

 the Quantocks now cover up these secondary rocks as far as 

 Clevedon, Bleadon Hill, Bream Down, Mole Hill, and Middle- 

 thope, three parallel ranges of Carboniferous Limestone (inland 

 islands) now attesting their deeply seated connection with 

 the Mendips, Broadfield Down and Clevedon, as outliers from 

 the main masses ; the steep and flat Holmes midway between 

 the English and Welsh coast, bridge over to Barry Island, 

 the once continuous subserial (now subaqueous) Limestones 



