MOOEE — ABNOEMAL SECONDARY DEPOSITS. 



471 



expect to find in a lagoon, or inland sea, in which the beds were being 

 very tranquilly deposited. The Avicula-contorta beds at the base of 

 the " White Lias " are not usually exposed ; but sections of these 

 will be given in describing the railway- cuttings near Bath. Amongst 

 the many locahties in this district where the " White Lias " can be 

 studied, may be mentioned Eadstock, Camerton, Farringdon Gurney, 

 Paulton, Norton, Willsbridge, N'ettlebridge, Saltford, Beech, Bedmin- 

 ster, and a very peculiar deposit at Broadfield Down, near Bristol. 



I now propose giving some of the most interesting sections in 

 the Coal-field north of the Mendips ; and though I have no special 

 faith in precise Ammonite or other zones of life, to which I refer 

 below, yet for the sake of establishing comparisons with the divi- 

 sions of other geologists, and the more readily to realize the uncon- 

 formable conditions of the beds in the distiict, I give the following 

 horizons based upon the supposed range of Cephalopoda therein. 



Upper ^ 



1. Ammonites Jiirensis. 



2. A. communis. 



Lias. 





f 3. A. spinatus. 



Middle 



4. A. margaritatus. 



Lias "^ 



5. A. capricornus. 





6. A. ibex. 





t 7. A, Jamesoni. 





{ 8. A. raricostatus. 





9. A. oxynotus. 



Lower 

 Lias. 



10. A. obtusus. 



11. A. Turneri. 



12. A. Bucklandi. 





13. A. angulatus (A. cateanus, Desk., A. Moreanus, D'Orb.). 





^ 14. A. planorbis (A. Hagenovii, Dum., A. psilonotus, Quenst.) 



a. Section of Kewper, RTicetic, Lower Lias, Middle and Upper Lias, 

 and Oolitic Beds at Camerton. 



Laferior Oolite 6. 



Tipper Lias 5. 



Middle Lias 4. 



Am. raricostatus 



Foraminifera-zoue , 

 Spirifer-bank 



Lower Lias 3. ■« 



Inferior Oolite in roadway leading from Tunley ft. in. 



to Camerton 3 



Uncovered beds embracing Upper Lias, about... 40 



Irregular beds of marlstone and clay 2 



( e. Nodular stone, with A. raricostatus 3 



Brownish clay 2 



Blue limestone with fish-scales, Ajptychus, and 



Ammonites semicostatus 6 



Blue clay with Foraminifera 8 



Indurated marl, " Spirifer-bank " of Quenstedt. 6 



( Grrey Lias 9 



Clay 1 



G-rey Lias 1 2 



Clay 2 



Grey Lias 3 



Ditto 6 



Clay 1 



Grrey Lias 3^ 



Clay 3 



Grey Lias 4 



Clay 2 



Corn Grit S' 



\ IClay 2 





1^ 



s 

 a 



