94 



LE BOTWOOD LIMESTONE AND COAL. 



The limestone at Le Botwood is extensively burnt for lime and is identical with that 

 of Pontesbury and Uffington, containing also the Microconchus carbonarius. It is 

 about two yards thick and lies from eighteen to twenty yards below the surface. A 

 three-feet bed of coal, found at eleven yards below the limestone, is of a sulphureous 

 quality ; and six yards still lower is a seam, twelve inches thick, of good coal. In 

 the limestone, besides the usual shells, the remarkable species of fish Ctenodus Mur- 

 chisonii (Agassiz) was found by the very Rev. Archdeacon Waties Corbet ; and Pro- 

 fessor Phillips detected, in the shale, remains of the Megalichthys Hibberti, &c. On 

 the western edges of this bay, amid the older rocks, coal has been worked near Pul- 

 verbatch, Wetrains, &c. ; and on the eastern side it has been detected, and was 

 partially worked in former days, running up in small transverse valleys towards the 

 Caradoc and Acton Burnell hills. One of the most curious of these thin patches is 

 displayed on the west bank of the brook at Pitchford. The whole carboniferous series 

 is there represented by a bituminous breccia, from ten to twelve feet thick ! which is 

 partially covered by the New Red Sandstone, and rests upon the highly inclined edges 

 of a greenish greywacke sandstone (Cambrian rock), similar to that of the Longmynd. 1 



The highly inclined edges of these Cambrian rocks, which rise to the height of only 

 from twenty to thirty feet above the brook, are, on the western side of it, covered with 

 the carboniferous breccia arranged in horizontal layers ; but as the works were abandoned 

 when I visited the spot, I could not observe the junction between these beds and the 

 inclined edges of the older rocks. This breccia is composed of fragments of the under- 

 lying Cambrian rock, on the surfaces of which are casts of ferns and other coal plants, 

 the whole being cemented by bitumen and decomposed sandstone. The beds were 

 formerly much quarried, and the breccia being transported to Shrewsbury, and there 

 subjected to heat, a liquid bitumen was extracted, which, when prepared, was sold as a 

 medicine under the name of " Betton's British Oil." Contiguous to this quarry is 

 a well, on the surface of which is a constant accumulation of bitumen exuding from the 

 adjoining strata. It will hereafter be shown that where points of trap rocks penetrate 

 the adjacent strata of the Cambrian system there are frequently bituminous exudations 

 near the points of contact. 



From the preceding details respecting the carboniferous deposits near Shrewsbury, 

 it appears, that the coal was formerly worked in those spots only where it actually rose 

 to the surface ; and that, even at the present day, the speculation has not extended to 

 any considerable distance beyond the mere outcrop. In the small irregular troughs at 

 Longnor, Uffington, Longden, Le Botwood, Pitchford, &c, where it is evident from the 

 nature of the sides of the trough, and also by the shallow depth at which the Silurian 

 and Cambrian rocks are met with, that no coal can exist, further trials would be absurd. 



1 I consider the green hard greywacke sandstone in the Pitchford Brook, on which the coal breccia lies un- 

 conformably, to be a part of the upper Cambrian System prolonged from the Longmynd. (See Map.) In the 

 brook Mr. Aikin remarked the intrusion into the schist of a green stone trap. 



