388 ME. L. EICHAEDSON ON THE INEEEIOE OOLITE [Nov. 1907. 



two; and was still further strengthened when he discovered in mate- 

 rial from Rodborough Hill which I gave him — found by knowing 

 the true stratigraphical position of the Upper Coral-Bed — a similar 

 assemblage. Of these fossils Spiriferina (?) oolitica, Moore, is the 

 most important, being — on account of its frequent occurrence — a 

 really useful zonal fossil. 



The remaining Inferior- Oolite beds may be grouped together as 

 the Doulting Beds, 1 but they admit of subdivision into Doulting 

 Stone, ^n«&a^«-JLimestones, and Bubbly Beds. 



(iii) Doulting Stone.— In the railway-cutting at Doulting 

 this subdivision is 44 feet thick, and in that neighbourhood it is 

 composed of the well-known Doulting Freestone 1 and associated 

 beds. The Doulting Freestone proper is only from 14 to 

 16 feet thick, but is an excellent building-stone, and, although 

 not so readily carved as the Bath Stone of Great-Oolite age, is 

 said to be much more durable — Wells Cathedral and Glastonbury 

 Abbey were mainly built of it. 2 The rock is a grey and pale- 

 brown, very sparry -looking limestone. The good building-stone is 

 fairly compact, the component materials (mainly comminuted 

 ossicles of Carboniferous-Limestone crinoids) 3 being well cemented 

 together by secondary calcite, which — according to Dr. J. J. H. 

 Teall 4 — is in optical continuity with the organic fragments. 

 Unfortunately, irregular cavities frequently occur, more or less 

 along horizontal lines, forming ' hollow beds,' which, together with 

 the false-bedding, make it necessary for the stone to be carefully 

 selected. 



(ii) Anabacia-Limestones. — These limestones are separated 

 from the Doulting Stone, because of their distinct lithological 

 structure — being white, and having the oolite-granules very even- 

 sized — , and the abundance in them of the little coral Anabacia com- 

 jplanata (Defrance). These faunal and lithological characters are 

 very persistent over the whole of the district under consideration. 



(i) Bubbly Beds. — This term is employed for the want of a 

 better, but it conveys a very satisfactory impression of the real 

 character of the beds. They are typically developed at the 

 Doulting-Bridge Quarry (p. 393) and in the workings north-east of 

 Farmcombe (about a mile farther south). They remind one very 

 forcibly, both as regards their lithological structure and their fauna, 

 of the typical Clypeus-Gnit of the Cotteswold Hills. 



In the matter of broad comparison it should be noticed that, 



1 It is hoped that, in order to prevent confusion, the terms ' Doulting Beds,' 

 ' Doulting Stone,' and ' Doulting Freestone ' will only be used in the sense here 

 suggested. 



2 ' Geology of the East Somerset & the Bristol Coalfields ' Mem. Geol. Surv. 

 1876, p. 124. 



3 ' The Jurassic Rocks of Britain— The Lower Oolitic Rocks of England 

 (Yorkshire excepted) ' Mem. Geol. Surv. vol. iv (1894) p. 89. 



4 Ibid. pp. 26-27 & 89. 



