216 THE RH.ETIC ROCKS OF PTLLE HILL, BRISTOL. 



marls are succeeded conformably, and indeed with an im- 

 perceptible gradation, bj about nine feet of somewhat indis- 

 tinctly bedded light greenish-grey marls — the " Tea-green 

 Marls " of the Grovernment Greological Survey. These latter 

 beds have hitherto been included by the Survey authorities 

 in the Rhaetic series, and this arrangement, coupled with 

 the inclusion also in that series of the true White Lias, 

 has no doubt materially exaggerated the extent of the 

 areas occupied by those rocks on tbe Survey maps. I 

 shall presently give reasons for removing these " Tea-green 

 Marls " from the Rheetics and classing them with the 

 Keuper. Above the Grey or " Tea-Green Marls," then, 

 come the Rheetic beds, which at Pylle Hill, as generally in 

 this country, consist of two well-defined series, namely, 

 black, thinly laminated " Paper Shales " or Avicula contorta 

 beds below, and light grey limestones and shales — my 

 " Upper Rhaetic Series " * — above. Before concluding this 

 paper I will give some account of these beds, and for further 

 details regarding them would refer you to the accompanying 

 section. (See page 229). 



The Rhgetic beds are succeeded by three or four feet of 

 rubbly, cream-coloured limestone and shale, which from 

 their peculiar light tint are generally distinguished by the 

 term, " White Lias." The section is completed by nine or 

 ten feet of the ordinary regularly bedded limestones and 

 shales of the Lower Lias, containing fossils characteristic 

 of the zone of Aiimionites planorhis. (See Fig., p. 217.) 



* It is to be understood that the division of the British Rhsetics 

 into an Upper and Lower Series here adopted, does not correspond 

 with a similar division which has been made of the continental 

 Rhsetics, but is merely a convenient method of distinguishing the 

 two very different portions of this series within the British area. 

 Probably the whole of the Rhsetic beds of Britain would belong to 

 the Upper B/hastic Series of continental authors. 



