TRIAS. 223 



The Lower Mottled Sandstone attains a thickness of about 650 

 feet at Bridgenorth ; in Cheshire it is 400 or 500 feet ; at St, 

 Helen's Junction it is about 250 feet ; in South Staffordshire 200 

 feet ; while in Nottinghamshire it nowhere exceeds 80 feet in 

 thickness. 



The Pebble beds attain a thickness of from 60 to upwards of 

 1000 feet. They are composed chiefly of brown and liver-coloured 

 quartzite and white quartz, the pebbles of which (according to Mr. 

 Aveline) are found either loosely scattered amongst unconsolidated 

 sand, or cemented into a hard conglomerate. In places the beds 

 consist of sandstone with few pebbles, and so gradually do they 

 pass into the sandstones below that there is no very definite line 

 of separation. The thickness of the Pebble beds at Bootle near 

 Liverpool has been estimated at 1200 feet; they form the most 

 constant division of the Bunter. 



The Upper Mottled Sandstone attains a thickness varying from 

 200 feet to 500 feet in South Staffordshire, and as much as 700 feet 

 at Delamere Forest. 



The total thickness of the Bunter beds is estimated at 1000 to 

 2000 feet. 



The Bunter Beds rest sometimes on the Permian Series in the 

 Midland counties, on the Carboniferous rocks in Derbyshire and 

 Lancashire, and in Shropshire and Leicestershire on the Cambrian 

 or older rocks. It is not always easy to separate them from the 

 Permian strata. Indeed, in Cumberland, North Wales, and 

 Nottinghamshire, there are signs of continuous deposition of the 

 Permian and Lower Bunter rocks.' 



Few, if any, organic remains are known to occur in the Bunter 

 Beds of this country. It is true that some plant-remains have been 

 recorded, as well as bones of Reptilia and foot-prints of Amphibia ; 

 but the evidence of the occurrence of many vertebrate remains 

 is not satisfactory, as they were discovered in beds formerly classed 

 as Bunter, but now recognized as Keuper.- 



The Bunter Beds may be represented in Cumberland in part by 

 the Kirklinton Sandstone, so named by Mr. T. V. Holmes, from 

 a village north-east of Carlisle. (See p. 212.) This sandstone, 

 is to be seen at Rockcliff and Netherby, but it is too soft to be of 

 value as a building-stone, and is therefore rarely quarried. The 

 age of the Kirklinton Sandstone is possibly Lower Keuper, and 

 the St. Bees Sandstone may with more probability be regarded as 

 Bunter. (See p. 213.) 



The Bunter beds are not exposed on the Yorkshire coast, but 

 they were proved to a depth of 600 feet at Middleton-one-Row on 

 the Tees. They stretch from the neighbourhood of Yarm and 

 Stockton-on-Tees, underneath the Red Marl and Drift of the Vale 

 of York, to the neighbourhood of Nottingham. They are well 

 developed in Staffordshire, Shropshire, Cheshire, and Lancashire. 



^ Rev. A. Irving, G. Mag. 1874, p. 315. 



^ Lyell, Student's Elements, 1 871, p. 351 ; Phillips, Geol. Oxford, p. 97. 



