1861.] 



KEY BOTEY DEPOSIT. 



11 



regular workings have been can-ied on there, as on the eastern side, 

 the clay found by boring being, for the most part, unsuitable for 

 commerce; it is highly stained with red matter, and grave%. 

 The little that is known tends to prove that the strike of the beds of 

 clay, sand, and gravel, on the western side, corresponds in direction 

 to an extended outhne of the hills on that side, the dip of the beds 

 being the same as at the Decoy, to the east. 



The nortli-ivestern part of the basin is better known : here occur 

 large deposits of " Bovey-coal " or lignite, — an accumulation of 

 tangled masses of vegetation, deposited in regular beds, of various 

 thickness, separated by rough clays and sand. At the Bovey Pottery, 

 where they have been worked extensively, the beds dip to the south- 

 east, and the strike of the strata runs about south-west. The dip 

 of the beds is about 11 inches in a fathom ; and their vertical thick- 

 ness is about 100 feet. The lower beds are those worked for fuel ; 

 the upper beds being very loose and irregular, and mixed with coarse 

 clay and quartzose gravel. The whole is covered by a deep " head " 

 of gravel, such as would be washed from disintegrated granite. 



Fig. 1. — Section of the Lignite-heds at the Bovey Pottery. (Taken by 

 Dr. Croker in 1841.) Scale -i-th inch to a fathom. 



a. " Head " of rough gravel. 



b. Imperfect beds of Lignite, separated by thin seams of rough clay and 



sand. 



c. Yellowish sand, 9 feet thick, with bluish clay, sand, and pebbles at the 



bottom. 



d. Ten beds of Lignite, separated by thin seams of clay, mixed with vege- 



table matter. 

 The beds dip to the South-east, with an inclination of 1 foot in 11. 



The order of deposition observed in this section coiTesponds 

 with what would be expected to result were a river, bringing 

 various kinds of sediment, to discharge itself into a deep lake. (See 

 further on, page 17.) In the regularity of the ten lower beds of 

 lignite, separated by thin seams of fine clay and vegetable matter, 

 are discerned the characteristics of deposits gradually formed, in deep 

 and comparatively still water, as the lake became filled up with 

 sediment, and the water became shallower, and the current there- 



