GEOLOGY OF THE BKISTOL COAL-FIELD. 321 



with carbonate of lime. Yery perfect specimens with the shell may- 

 be easily obtained in great numbers and [perfection. The following 

 fossils are the most common in a very long list obtainable in this 

 spot. 



Chonetes Buchiana (Dav.), sordida (Sow.), var perlata, 

 jpapilionacea (Kon.) ; Orthis resupinata (Mart.) ; Streptorhyncus 

 crenistria (Dav.) var. arachnoidea (Dalm.) ; SanguinoUtes transversa 

 (Portl.) 



10. — [520]. — Pleurodonled. — This is marked out on account of 

 containing Ehynchonella pleurodon, which is not found in the Clifton 

 rocks so abundantly as in the Derbyshire and many other limestones. 

 The two chief fossils are : — Rhynchonella pUurodon (Pisch.) ; 

 Cladodus conicus (Ag.) 



11. — [535]. — Fenestella led, so called from the remarkable 

 abundance of bryozoa that are foand in it. Excellent specimens 

 may be collected on the railway bank, where the little branched 

 polypidoms attract the eye, standing oat in relief on the weathered 

 slabs of limestone. Prom this bed are also collected the heads of 

 Encrinites in a good state of preservation. 



Ptylopora pluma (McCoy.), flustraformis (Phill.) ; Fenestella 

 flahellata (Lonsd.), irregularis (Phill), polyporata (Portl), 

 membranacea (Lonsd.); Retepora prisca (Lonsd.); Ceriopora 

 interporosa (Goldf.), rhomhifera (Gold,) ; Streptorhyncus crenistria 

 (Phill.) ; Orthis resupinata (Mart.) ; Encrinites (various.) 



12. — [639]. — Trilohite led. — This limestone is very rich in the 

 Phillipsia, of which only the pygidia will probably be found. The 

 pretty little Chonetes perlata or as it is sometimes called C. 

 Hardrensis is very plentiful. A good spot for this bed is on the top 

 of the hill where it crops up at the back of Avonhurst house, Sneyd 

 Park. Although varieties of the same trilobite, yet the difference as 

 pointed out in Portlock's report on Tyrone, &c., are so marked 

 that the names are retained as a guide to the visitor. 



Phillipsia pustulata (Schlot.), var. Brongniarti (Pisch.) var. 

 seminifera (Phill.) ; Chonetes sordida (Sow.), ^ox. perlata (Phill.). 

 13. — [639] . — Oracanthus led. — This is another of our well marked 



