3I00RE ABNORMAL SECONDARY DEPOSITS. 529 



giilarities of the limestone, and passing down any fissures observable 

 therein. At caverns 5 and G the Carboniferous Limestone still 

 forms the sides, at the latter becoming red and regularly bedded, 

 with a gradual dip seaward. The Sutton Stone is here reduced 

 to one-half its former thickness. At cavern No. 7 the limestone 

 becomes much inclined, and the whole of the Sutton series is 

 included in four or five thick beds. 



The beds inckided by Mr. Tawney in the Southerndown series 

 have now assumed considerable thickness ; but the Sutton Stone is 

 still thinner, and rests upon almost vertical Carboniferous Limestone. 

 At caverns 8 and 9 the beds are faulted and thrown down, and the 

 Sutton Stone again becomes thicker. From this point the beds 

 again rise and are somewhat horizontal towards Dunraven. It may 

 now be observed that the lower beds of Lias have gradually 

 changed in colour and in structure, becoming a dull olive, and in 

 texture almost like Carboniferous Limestone. Instead of a deposit 

 like the Sutton Stone, the beds have become less conglomeratic, and 

 only thin bands or patches of conglomerate have been washed in here 

 and there, resting upon the surfaces of the beds, which soon again 

 pass into their ordinary conditions; and hence to Dunraven the 

 Sutton Stone is no more seen. My view of its local deposition is 

 strengthened by the coast-section given by Mr. Tawney, in which it is 

 seen that the Sutton Stone should again have come to the surface 

 under Southerndown : but this is not the case ; and in the very 

 lowest beds at this point that the tides at low water would allow us to 

 reach, Gri/jph'rea incurva, Pholadomya, Rhynchonella variahilis, Ostrea, 

 and other evidences of Liassic life were found. 



b. Organic Itemainsfrom the Sutton Stone. — High up in the vertical 

 section given by Mr. Tawney, and immediately under the Ammo- 

 nites-Bucldandi beds, that gentleman has indicated a zone of Ostrea 

 liassica. 1 have shown the special horizon of this shell at Camel 

 and Bedminster, and also at Stormy, Laleston, and Llanbethian, near 

 Sutton, where it is found below the Ammonites-jjlanorhis beds and 

 at the base of the Liassic series ; its presence therefore on the horizon 

 thus pointed out would necessarily place all the beds on which it 

 reposes, supposing it to occupy the same position as in the above 

 sections, below the Liassic series. This shell is abundant in the 

 Sutton Stone, and passes upwards ; but I was unable to recognize 

 it as occupying a special horizon like that indicated in the above 

 sections. 



Before the deposition of the Sutton Stone, the species of corals 

 found therein had attached themselves to the floor of Carboniferous 

 Limestone or to its fissures ; and under the same circumstances eleven 

 species of Mollusca which recur in the Sutton Stone have been found. 

 In addition to these, there are two (Fleurotomaria ohliqua, Terq., 

 and Trochus slmstrorsus, Desh.) which I have not yet recognized 

 elsewhere. In the very mineralized matrix of the vein-stuff under 

 the Sutton Stone, Entomostraca are to be recognized. 



The species from the Sutton Stone are not so numerous as miglit 

 have been expected when the very fossiliferous nature of the bed was 



VOL. XXIII. PART I. 2 



