Vol. 67.] WEST, MID, AND EAST SOMEKSET. 27 



there that must be drawn for the present the line between Rhsetic 

 and Keuper. Further investigation may lower the line ; but this 

 reduction in thickness prepares us for the fact, that in the railway- 

 cutting at Dunbali the Sully Beds are probably represented by 

 a bed only 10 inches thick. 



The uppermost foot or so of Sully Beds at Lilstock is crowded 

 with specimens of Pteria contorta, and the topmost layer is identical 

 lithically and palaeontologically with the layer at the top of the 

 Sully Beds at St. Mary's Well Bay, Sully. It is impossible to 

 distinguish between hand-specimens from the two localities. 



The Bone-Bed is a very hard, grey, siliceous sandstone, not unlike 

 the foreshore Bone-Bed at Blue Anchor ; but the sand-grains are 

 smaller, and the vertebrate-remains more comminuted. Obscure 

 moulds of Isocyprina occur, with the tests replaced by iron -pyrites ; 

 and associated with them are small coprolites, the usual fish- 

 remains, and a few small quartz-pebbles. 



In this country the deposits between the main Bone-Bed (15) 

 and the Sully Beds, or, if they are absent, the Keuper, are best 

 described as the ' infra Bone-Bed deposit,' for an attempt at more 

 minute correlation of their component beds is not generally attended 

 with very satisfactory results — the strata varying so much from 

 place to place. However, in so far as Lilstock is concerned, I 

 have made some suggestions as to their individual correlation; 

 but it must be remembered that these are only suggestions, nothing 

 more. 



Bed 9 is very conspicuous, and I do not think that there is 

 much doubt that it is on the same stratigraphical horizon as the 

 similarly-numbered beds in the Dunbali and Charlton-Mackrell 

 railway-cuttings. Horizon 5 b — the Cardium-cloacinum Bed — is 

 not distinctive : at least I did not discover its familiar, fossiliferous 

 little nodules. 



The component deposits of the Cotham Beds, again, agree very 

 fairly with their equivalents elsewhere, and there are no signs that 

 a disturbance affected the ordinary process of their deposition. 



The break occurs higher up indeed — at the top of the Cotham 

 Beds. Here is very instructive and quite unmistakable evidence 

 that, after the formation of the Cotham-Marble equivalent, and 

 before the time of deposit of Bed 10 of the Langport Beds, there was 

 a disturbance of the sea-floor resulting in a remarkable bed consisting 

 of limestone-masses of all sizes up to 18 inches in vertical length, to 

 which pieces of Cotham-Marble equivalent are frequently adherent. 

 In other parts of the section the Cotham-Marble equivalent is joined 

 on to the hard basal stratum of the Langport Beds. 



It should be noticed also that the lower stratum of the Sun-Bed 

 here, as at St. Audrie's Slip, is somewhat conglomeratic. 



The Watchet Beds are of the same thickness as at St. Audrie's 

 Slip, but are usually separated by a limestone-bed from the succeeding 

 Paper-Shales, which are in turn capped with the massive ' Bottom- 

 Lias' limestone. 



