218 REV. J. F. BLAKE ON THE 



its character is best observed at Coney Hill. Here about 8 feet are 

 exposed, showing several layers of alternately large and small rubble, 

 the large being composed of the internal casts of shells, which in some 

 cases retain fragments of the shell attached ; and yet, when they 

 are extracted immediately from the rock, there is no sign of the rest 

 of the shell in the matrix. We are therefore forced to the conclu- 

 sion that the deposit is a redistributed one, the shells having become 

 fossilized in an earlier matrix, from which they have been rolled 

 out. The peculiar character of the fossils, as will be seen, points 

 to the same conclusion. At an admirable section at Lodge Hill, 

 made for drawing up stone for the building of a mansion at the 

 summit, 12 feet of these rubbly beds appear, the base being im- 

 bedded irregularly in the underlying sand. They may also be re- 

 cognized by their fossils, occupying the Great Western railway- 

 cutting east of Aylesbury. At Brill, this part of the series can only 

 be traced in a rough cliff- face over the brickyards ; but some rubbly 

 beds of the same character have a thickness at one place of 6 feet 

 6 inches. The following is the fauna observed : — 



Fossils of the Rubhly Beds of BueJcinghamshire, 



c. Trigonia Pellati {De Lor.). 



incur va (Ben.). 



Voltzii (Jff.). 



muricata ( Gold/.). 



gibbosa (Sow.). 



Manseli (Lye). 



Micheloti (De Lor.). 



Perna Bouchardi (0pp.). 

 Lima rastica (Sow.). 



ornata (Buv.). 



bifurcata (Blake). 



Pecten lamellosus (Sow.). 

 Ostrea solitaria (Sow.). 

 Plicatula Boisdini (De Lor.). 



echinoides (Blake). 



Serpula quinquangularis (Gold/.). 

 Glyphea, sp. 



Ammonites boloniensis (De Lor.). 



pseudogigas (Blake). 



triplex (Sow.). 



biplex (Sow.). 



pectinatus (P^-)- 



Pleurotomaria rugata (Ben.). 



Natica turbiniformis (Bom.). 



Thracia ten era (Ag.). 

 c. Pleuromya tellina (Ap.). 



Sowerbya longior (Blake). 

 c. Myoconcha portlandica (Blake). 



Cyprina implicata (Be Lor.). 



Brongniarti? (Pict. et B.) 



Unicardium circulare (B'Orh.). 

 c. Oardium Pellati (De Lor.). 

 r. dissimile (Sow.). 



Mytilus jurensis (Bom.). 



boloniensis (De Lor.). 



In this fauna the scarcity of Gasteropods is at once noticed ; this 

 may be accounted for by their having been destroyed in the break- 

 ing up of the old beds. The Ammonites pectinatus is an important 

 introduction for the purpose of correlation. Its presence and the 

 change of the common Cardium and Trigonia into other species, 

 mark an earlier date ; and several fossils which are new or peculiar 

 have the same tendency. 



No. 5. The section at Lodge Hill, before mentioned, shows a suc- 

 cession of sand and shell-beds, doubtless of the same character as 

 No. 4, and of very little consequence, though here reaching 12 feet 

 6 inches. They are separated, because, on the one hand, they are not 

 glauconitic, and, on the other, they are less constant than the over- 

 lying rubble beds. They are seen also in the cutting near Aylesbury, 

 but towards the south they appear to die out, thus being comple- 

 mentary to the sand below. 



