88 Prof. Sedgwick on the Carboniferous Chain 



On the descending line there is a fine exhibition of the slate quarries in 

 No. 8. c. Close to the chapel the river runs in the grit bands (No. 2. c.) 

 under the black marble ; but in ascending- to Garsdale Head (where the road 

 turns off to Kirkby Stephen), all the beds up to the fourth Mosdale Moor lime- 

 stone (No. 7.) may be observed to cross the channel in succession. 



Both sides of Risell are much covered with alluvial matter and vegetation ; 

 but independently of the localities above indicated, the position of the respec- 

 tive groups is defined by the rows of inverted green cones, provincially called 

 swallow-holes, which often mark the presence of the limestone bands when no 

 rock is visible at the surface. From many places, on the line of section, five 

 rows of these inverted cones, each indicating the presence of one of the cal- 

 careous groups above the Scar limestone, may be seen on the sides of the 

 neighbouring mountains*. 



In ascending from Garsdale chapel to the top of Baw Fell we may find, by 

 the sides of various torrents, good sections of all the groups, from the black 

 marble to the twelve-fathom limestone. A thin coal band breaks out, here and 

 there, in the group (No. 4.) above the black marble beds. On the west flank 

 of this mountain, the coal bed (No. 6. b.) under the Mosdale Moor limestone 

 has been worked extensively ; and on the same flank the coal bed under the 

 twelve-fathom limestone has been attempted f. The quarries in the four - 

 fathom limestone, from which large encrinital blocks are extracted for the use 

 of the Kendal marble works, also deserve notice. 



The groups of strata above the twelve-fathom limestone are of the aggre- 

 gate thickness of 500 or 600 feet, and terminate at the top of the mountain 

 in fine, horizontal, tabular masses of millstone grit, subordinate, if I mistake 

 not, to the second group of that rock (No. 15.). All the upper parts of the 



* The origin of these cones is very clear. The several limestone groups abound in crevices and 

 fissures, through which the waters, descending from the higher regions, immediately sink, and 

 trickle down among the lower strata, till they meet some impervious bed which throws them out 

 again to the surface. Now on the sloping sides of the mountains these groups generally form long 

 horizontal terraces, more or less buried under masses of alluvial, incoherent matter: and through this 

 covering the waters freely percolate, till they meet the surface of the limestone beds ; when they sink, 

 as above described, through some of the crevices, and carry along with them the finely comminuted 

 portions of the superincumbent materials. In this way the alluvial beds are slowly undermined, 

 and sink down into inverted cones — the inferior portions of which, being sheltered from the elements, 

 and kept dry by the action of the crevices below, become covered with a fine green sward abound- 

 ing in such plants as are commonly found only in the lower regions of the mountains. 



t Not far below the works in No. 6. 6. a trial was made, a few years since, in some highly in- 

 clined, carbonaceous shales, probably subordinate to No. 4. of the general section. The coal was 

 abundant, but of very bad quality, and difficult to work ; being close to the disturbance produced 

 by the passage of the great Craven fault. See the preceding Memoir, p. 60. 



