Vol. 60.] 



SECTIONS IN THE BRISTOL DISTRICT. 



175 



quarter of a mile away, at a level about 20 or 30 feet below the 

 Black Shales. The succession is : — 



About 1 yard of surface-soii. 



V. Red marl : 2 feet. 

 IV. Celestine-bed : 2 to 8 inches. — Rather inconstant, confined to the one 



horizon. 

 III. Red marl : 3 inches. 

 II. Hard typical green marl : 4 inches. 

 I. Red marl: 15 feet. — Contains a few calcareous plates and nodules. At 

 the top it is full of nodules about the size of a cricket-ball, composed 

 of carbonates of strontium and calcium, in the proportion of 37'63 per 

 cent, of the former, and. 62'36 per cent, of the latter. 



The celestine, IV, contains an unusual proportion of strontium-carbonate 

 (SrS0 4 =68"43 per cent. ; SrC(X = 31 'o(i), and is badly crystallized, but shows 

 a distinct blue colour. 



The whole Rhaetic Series described above dips gently east- 

 north-eastward at a somewhat variable angle, usually about 10°. 

 On the Gotham-Marble horizon the rare mineral baryto-celestine 

 may be found, chiefly in drusy cavities inside concretions. 



Since writing the foregoing account, I have found in the Pecten- 

 valoniensis zone two or three ovoid, well-rounded blocks looking 

 exactly like charred wood. On analysis, these turn out to be chiefly 

 carbon and carbonate of lime, with no phosphate, so that they can 

 be neither bone nor coprolite, and indeed must be fragments of 

 drifted wood. As they measure, though very incomplete, | by -J- inch, 

 there must have been trees or very big bushes growing near the 

 water, or by streams, at that time. 



Messrs. Tutcher & Vaughan have described the Lower Lias and 

 White Lias of these sections in a paper published in February 1903 

 by the Bristol Xaturalists' Society (o2). 



(B) Stoke Gifford. 



In a railway-cutting recently made in connection with* the new 

 line from Lilton, near Bristol, to Wootton Bassett, the Rhietic has 

 been well exposed at Stoke GifTord, quite close to Filton. 



The whole series dips at 5° towards 10 c west of north. 



The Lias has been described by Messrs. Reynolds & Vaughan (50). 

 and it is unnecessary to repeat their description, except to add that 

 I found Monotis decussata in their ' Ostrea-beds/ 



The succession is as follows : — 



N. Cot ham Marble, in a 

 continuous band. Top 

 not so ridged as usual. 



M. III. Grey laminated 

 marl. 



II. Thin but constant 

 band of siliceous lime- 

 stone. 



Feet fochei 







Rhynchonella calcicosta ; Axinus s 

 Monotis decussata. 



(Barren.) 



