CARBONIFEROUS LIMESTONE. 



159 



toadstone, of which two or three beds occur, impart additional 

 interest to it. It attains a thickness estimated by Prof. Green at 

 about 1600 feet.^ It is occasionally dolomitic. 



Chee Tor in Miller's Dale is a fine cliff of the rock. Excepting 

 Dovedale, the most interesting scenery lies in the valley of the 

 Wye, between Bakewell and Buxton, including Monsal and Miller's 

 Dales. A marble quarry in Tideswell Dale shows a remarkable 

 bed of red columnar clay, resting on highly crystalline limestone, 

 and capped by basalt (toadstone). (See sequel on the Igneous 

 Rocks.) 



Fig. 23.— Section of the Carboniferous and Triassic Strata lying on 

 THE Edge of the older Rocks of Charnwood Forest. 



(Prof. E. Hull.) 



Charnwood Forest. 



Grace Dieu 



1. Triassic Breccia. 



2. Upper Limestone Shales. 



3. Carboniferous Limestone. 



4. Slaty rocks, etc. (See p. 43.) 



In South Wales, the Carboniferous Limestone contributes much 

 to the scenery between Bridgend and Cardiff. Many fossils have 

 been collected in the vicinity of Swansea.- On the northern 

 escarpment of the Limestone the Castell Coch Rock and the 

 Trefil Limestone are well known to the south-west and south-east 

 of Brecknock. On the Pembrokeshire coast Stacpole Cliffs are 

 remarkable for many natural arches and caverns. (See Fig. 29.) 



Near Haverfordwest the Carboniferous Limestone has become 

 much attenuated.^ The stone is quarried in many localities near 

 Pembroke. At Caldy Island, however, the Limestone is about 

 2000 feet in thickness ; while near Llangadock, on the north side 

 of the coal-basin, it becomes reduced to 510 feet. In the Forest of 

 Dean it is under 400 feet; and in the northern part of Glamorgan- 

 shire, 500 to 600 feet. In Monmouthshire it is 1000 feet, and in 

 the Mendip Hills about 3000 feet in thickness. 



The main mass of the Mendip Hills in Somersetshire is formed 

 of the Carboniferous Limestone, which is exposed in the picturesque 

 vales of Vallis, Whatley, and Nunney near Frome, in Burrington 

 Combe, in the Ebber Rocks, and in the grand cliffs of Cheddar. 

 The rugged hill of Dulcot near Wells, and Crook Peak near 

 Axbridge, are formed of the Limestone, which stretches out to the 



^ See Geology of N. Derbyshire (Geol. Survey), by A. H. Green, C. Le Neve 

 Foster, and J. R. Dakyns ; also Geol. Derbyshire, by J. M. Mello, p. 28. 

 - See G. H. Morton, Science Gossip, Nov. iSSo ; Proc. Liverpool G. S. 1881. 

 3 De la Beche, T. G. S. (2), ii. i. 



