18 



THE GEOLOGIST. 



an immense quantity of hardened nodules ; and, whilst the 

 su1)jacent beds are so prolific in species of Ammonites, this 

 on the contrary, abounds in bivalve shells. It contains indeed 

 a greater number of species than all the other beds united, 

 and amongst the number we have, Area (2) — Modiola (2) — 

 Gervillia (2) — Terebratula (2) — Ostrea {\)—Gryph(2a (1) — 

 Unio {\)—Avicida (2) — Pholodomya (1) — Lutraria (2) — Hip- 

 popodium (I). 



The Hippopodium of this bed differs very materially from 

 that found in the lower beds of the lias, in having the beaks 

 of the shell larger and more remote. We have hence called 

 it i^. divaricatum. 



The remaining fossils of this bed include Belemnites (2) — 

 Nautilus (1) — Ammonites (3) — Pentacrinus (1). 



F. A bed of stiff blue clay, ten feet in thickness, succeeds 

 the characteristic fossil of which is a small variety of Pla- 

 giostoma antiqua. 



II. The Middle lias. 



The lias marlstone follows next, and is so distinct in its 

 lithological character^ and furnishes so many and such 

 varied fossil remains, that it claims a somewhat lengthened 

 notice. It is composed of several beds of marls and 

 clays, and dips at an angle of 12°. It may be traced 

 along the whole range of the Cotteswold^ except where 

 it is covered by the debris of the oolite, resulting from the 

 numerous slips which have taken place in that formation. 

 The oohte outlier of Bredon rests upon this bed, and it also 

 appears at the base of Dumbleton Hill, again is lost by the 

 intervention of a vallej^, after crossing which it crops out in 

 the lower portion of the Cottesv/old range during its entire 

 length, until it is again separated by slight valleys, and sub- 

 sequently re-appears, and forms the l)ase of some small hills 

 to the S., as at Churchdown, Robin Hood's Hill, &c. 



