74 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [DcC. 6, 



the lignite associated occasionally with the Sutton and Southern- 

 down series, as I believe the Galena is confined almost entirely to 

 these beds ; it occurs in disseminated crystals and small strings, but 

 not in workable veins. 



It is plentifully scattered at Sutton and along the coast, and has 

 before been noticed at Candleston *, where an attempt was made to 

 work it. A more recent failure is that of Langan : a shaft was 

 sunk and buildings half erected before the attempt was abandoned ; 

 this shaft passes through parts of the grey series, showing the rock 

 to be a fine conglomeratic mixture of small flint-fragments with cal- 

 careous matter, and it reaches to the white series. 



These beds are very fossiliferous ; I have obtained from them 

 some species new to Britain, and others, which are described in the 

 sequel. Owing to the porous nature of the rock, the original shell- 

 substance of the fossils is often dissolved away ; this has added much 

 difficulty to the determination of the species. 



The most characteristic and common fossils are Pecten Suttonensis, 

 Ostrea multicostata, a Muscheikalk species, Lima tuherculata, a 

 coral. Patella Suttonensis, PUcatula intusstriata, and P. acuminata. 



The Sutton Stone was formerly apparently more appreciated as a 

 building- stone than it is now ; it was used in several Norman castles 

 in the county, having been conveyed considerable distances by land : 

 it was also used in Neath Abbey (the characteristic fossils may be 

 seen in stones lying about the ruins), and, I am told, in Swansea 

 Castle ; to these it was, no doubt, taken by water. 



Besides the Sutton quarries, which are still worked, there is a 

 good quarry east of Tythingstone church which has not been used 

 for a long time, but from which much good stone has been taken. 



7. SoutJierndown Series. — As the term Sutton Stone is applied only 

 to the building- stones, I have divided off the rest of the series which 

 intervenes before the commencement of the Lias here ; and, for con- 

 venience of reference, I call it the Southerndown series ; this has 

 hitherto been regarded as Lias. 



At the base we have a bed of chert-gTavel, or rough shale full of 

 small fragments of chert, together with larger pieces ; it is 9 inches 

 thick. This physical line may be also said to separate the softer, 

 more fossiliferous, and whiter beds below, from the harder, darker, 

 and perhaps less fossiliferous beds above. 



As this series is not worked at all on the coast, nor much quarried 

 inland, our knowledge of its fossils is much less full ; however, 

 PUcatula intusstriata occurs throughout it. 



This series differs lithologically from the Sutton Stone in the 

 beds being much harder and more irregularly bedded, and they are 

 frequently subcrystalline and separated by thin arenaceous part- 

 ings ; again, the fragments of black chert are more sparingly scat- 

 tered. On the other hand, it differs from the Lower Lias beds — 

 which are earthy limestones separated generally by argillaceous 

 shales, having no fragments of black chert, and not being conglo- 

 meratic. The two series differ also entirely in their fossils. 

 * Loc. cit. p. 273, in note. 



