3I00RE — ABXOEitAL SECO>'DAEr DEPOSITS. 457 



horizons where they occur as deep-water deposits south of the !M!en- 

 dips and therefore beyond their influence, and those of the same age 

 which either rest upon or are in contact with the Carboniferous 

 Limestone, and then their representatives withia the Coal-basin. 



1. The Trias, a. South of the 2Iendi_ps. — The best districts for a 

 study of the upper members of this group in the ^est of England 

 are along the numerous escarpments bounding the moorlands of 

 "Wedmore south-west of the ITendips, along the whole hne of the 

 Polden Hills to Bridgewater, and again from Compton Dundon by 

 way of Somerton, Langport, and Hatch Beauchamp towards Taun- 

 ton. Throughout the greater part of these districts the Lower Lias 

 occupies the tableland, the Pihsetic beds coming in immediately 

 beneath and skirting the edge of the escarpments. The beds of the 

 Keuper are also seen in narrow belts leading down to the base of 

 the escarpments. As these beds are usually, if not entirely, on the 

 same horizon as the variegated marls, and represent them (the highest 

 member of the Tiiassic series), nothing could be known from any 

 superficial examination regarding their general thickness, or the 

 probability there might be of an extension of workable Coal-mea- 

 sures in this direction beneath them. As this point is one of so 

 much importance, and is now receiving general attention from the 

 scientific world, it is fortunate that the following section of the 

 upper members of the Trias in this direction has been preserved. 

 We are indebted for it to the late Earl of Hchester, on whose 

 lands at Compton Dundon an attempt to discover Coal was made in 

 the year 1815, the vtork being under the direction of the late ]Mr. 

 William Smith. The section and the notes appended thereto were 

 then recorded by the latter gentleman. 



Section of Strata bored through at Comptoii Dundon in 1815. 



Beds in the escarpment : — yds. ft. 



Lias (Ehtetic clays) 



Clav stone 



Plaster 



Clay 



Strontian }. 30 



Clay I 



Eed earth i 



Clay I 



Eed earth J 



Top of the pit. 



Eedearth 56 2 



Alabaster, 4 feet. 



Eed earth mixed with gypsum, to 69 



Ditto, ditto, to '. 97 2 



Light-grey marl, 3 ft. 6 in, 



Eed earth, to 110 2^ 



Blue rock, 6 in. 



Eed earth -with gypsum, to 134 



Blue clunch, 9 ft.' 



Eed earth, to 144 



Yery hard blue clunch, 3 ft. 



Eed' earth, to 150 



Softer blue clunch, 3 ft. 



Eed earth, to 153 



