Geology. 223 



remains at Street, near Glastonbury and elsewhere, have 

 been obtained are wanting, and generally the Ammonites 

 Bucklandi or Lima gigantea beds are the first to be found 

 at the base. An exception may be made of the Newbridge 

 Hill cutting before alluded to, where the Ammonites angu- 

 latus bed comes in. The upper clays of this formation 

 occur everywhere throughout our basin, weathering to a 

 brown or foxy colour on the top ; and it was on this horizon 

 that William Smith constructed the bed of the Somersetshire 

 Coal Canal on the south side of the city. About forty in 

 number these beds vary in thickness in every quarry, the 

 lower portion consisting of irregular limestones with dark 

 blue clay partings, the upper, generally brown, may be seen 

 on both lines of railway from Bath to Bristol, Weston, 

 Twerton, Saltford, and Keynsham, and in the cuttings of 

 the line between Bath and Evercreech. We know also that 

 they exist beneath the superficial covering of our valley, 

 as proved in two memorable instances. A well sunk in 

 1838 in the western part of the City showed the following 

 section : — 



1. Black Marl (upper blue marls of the Lower Lias) 50 ft. 



2. Thin beds of blue Lias, succeeded by blue Lias 



nearly solid, with White Lias below ... 40 ft. 



A fruitless attempt to win coal at Batheaston in 181 2 gave 

 the following succession : — ■ 



I. Upper Marls (Middle and Lower Lias) ... 210 ft. 



3. True Lias beds, including White Lias, 10 ft. ... 47 ft. 6 in. 



In both these cases it may here be incidentally remarked 

 that water of a high temperature was found when the red 

 beds below were tapped in the Kingsmead sinking at a tem- 

 perature of 80°. The chief peculiarity of these beds in our 



