OKOLOGlY OF THE AVON BASjN. 23 



Routliorly qnarries the bods dip gently 15° S.E. In one of 

 tlio more northerly they are contorted, and then seem to 

 curve round so as to dip 45° N.N.E. In two of these 

 quarries wo once more come upon the Bryozoa bed. 



The occurrence of this remarkable bod in the Avon 

 section was first indicated by Mr. W. W. Stoddart, who 

 described it and some of its contents in The Annals and 

 Magazine of Natural History, vol. vii. (1861), p. 48G. It 

 consists of a reddish limestone, in which arc imbedded a 

 vast number of fossils of minute organisms, chiefly crinoidal 

 remains, with polyzoa fragments. The following is Mr. 

 Stoddart's list of forms always present in the rock beneath 

 Cook's Folly : " Geriopora rJwmhifora (Goldf .) ; Tlatycrinus 

 laivis (Mill); Foteriocrinus isacolms? (Aust.) ; Leperditia 

 Okeni (Munst.) ; Gypridina ovalis (Stod.) ; Gytherella lunafa 

 (Stod.) ; Natiaopsis plicistria (McCoy), (Young) ; Productus 

 (Sp. ?) ; Spirorhis triangnlatus (Stod.) ; rsaminodus porosus 

 (Ag. ) ; Gladodus conicus (Ag.)." M.r. Stoddart's list I qnot« 

 as it stands (Froc. B. N. S., New Series, vol. i., p. 320), 

 without criticism or addition. The organic remains are ex- 

 quisitely preserved. On treatment of the rock with dilute 

 acid the limestone dissolves, and the microzoa remain as a 

 deep red ferruginous rosichTC. 



So far a,s I am awaro, the Ihyozoa bed has not been 

 recorded elsewhere than in tho Avon section. In the map 

 appended to this paper I have recorded six other localities, 

 and in that appended to my paper on the Portbury and 

 Clapton District (Con. 3), two more. Where I have been 

 able to measure it, the thickness has been from 5 to 8 feet. 

 The size and number of the contained microzoal fragments 

 varies, but the essential character is remarkably constant. 

 In all cases it is a reddish limestone, in which are imbedded 

 the insoluble ferruginous fossils. 



