212 Geology. 



beds laid down, the Carboniferous Limestones, though 

 generally concealed by newer formations, there are many 

 outcrops of these beds here and there in our immediate 

 neighbourhood indicating their presence beneath ; in every 

 case they contain the usual fossils, Brachiopods, Corals, 

 and Crinoids, and are found dipping at a more or less high 

 angle towards the Coal basin inside. Besides the great 

 mountain mass to the south, they crop up at Wickwar, 

 Yate, Tynings south west of Codrington village, and at 

 Wick ; and, within close proximity to the city, on the 

 northern slopes of Lansdo'wn, at Granham, or Grammar 

 Rocks. The exposure at this latter place presents the 

 usual condition of solid blue beds, 150 ft. in thickness, and 

 dipping at an angle of 55° W.N.W. 



It has been stated by Chas. Moore ( Wrighfs Historic 

 Guide to Bath, p. 388) that in a fruitless attempt to sink for 

 coal at Batheaston, in the year 181 2, these rocks were there 

 found at a depth of 334 ft. ; but the details of that sinking, 

 as given in Conybeare and Phillips (Geol. of Eng. and Wales, 

 J>. 262) does not bear out this statement. The depth of the 

 shaft is there given as 287 ft., and the series of beds pierced 

 through extended from the Lias to the new Red Sandstone. 

 The thickness of the whole series of Carboniferous Lime- 

 stone in this district may be set down as 3,000 ft. The 

 Lower Limestone Shales, consisting of clays and shales 

 alternating with impure beds of limestone, may be estimated 

 as 500 ft. thick ; the middle beds, composed of solid blue 

 Limestones, about 2,000 ; and the upper Limestone Shales, 

 alternations of Shale, Sandstone, and impure Limestone 

 gradually passing up into the overlying Millstone Grit, about 

 500 ft. The Sandstone at Tytherington, called " Firestone " 

 locally, is hardly distinguishable from Millstone Grit. 



