264 GEOLOGr OF THE BRISTOL COAL-FIELD. 



The most northerly point in which we come into contact with 

 the Upper Llandovery beds is at Malford Common and Swanley 

 Green. It then continues through the Tortworth district, where 

 it may be studied for a distance of three miles, from Conderford 

 Bridge to Whitfield. The Upper Llandovery- may be considered 

 as the passage beds between the Lower and Upper Silurian. 

 They consist of micaceous sandstones and shales, having altogether 

 a thickness of lOGO feet. Some are nearly all sound, while 

 others are very argillaceous and fissile. The most fossiliferous 

 beds are on the Sandstone, where they may be easily found by 

 the purple colour and burnt appearance of the stone. These and 

 the thin shales may be found near Damory Bridge. Here the 

 fossils are extremely abundant and tolerably well preserved. An 

 -excellent spot is at the road side, a few yards west of Damory 

 quarry. So rich is this spot that the student may spend an hour 

 or two over a good block of the stone, and fill his vasculum with 

 a good suite of typical fossils. From this spot to the trap quarry 

 the mineralogist may find a most interesting series of specimens 

 shewing the gradual change of loose sand into solid and compact 

 quartz. 



The following is a list of the fossils that most frequently may 

 be met with in the Llandovery beds of the Tortworth 

 ■district : — 



Pfctraia bina (Lond.) 



subduplicata (Mc Coy.) 

 elongata (Phill.) 

 Tavosites Gotblandica (McCoy.) 

 Forbesi (M. Edw.) 

 Hisingeri (M. Edw.) 

 Tentaculites Anglicus (Salt.) 

 Cornulites serpularius (Schl.) 

 Phacops Stokesii (M. Edw.) 



Weaver! (Salt.) 

 Stricklandinia lens (J. de C. Sow.) 



