48G 



PEOCEEDINGS OF THE GEOLOGICAL SOCIETY. 



30. Liassic vein, 2 feet. 



31. Carboniferous Limestone, 18 feet. 



32. Rocks not exposed, 50 feet. 



These are again continued in an adjoining quarry for a length of 

 450 feet, with a repetition of the vertical infilHng, though not of so 

 decided a character. 



Looking across the little stream vrhich runs at the base of the above 

 sections, a finely arched or anticlinal mass of Carboniferous Lime- 

 stone may be seen, the upper beds having been worked back, leaving 

 a wall of crescent-shaped thickly bedded limestone. On the inchned 

 face of a bed of limestone beneath this wall the members of the 

 British Association assembled. Immediately below them was a thick 

 Liassic dyke composed of yellow or pink limestone, or changing into 

 the various materials of which our mineral veins are composed. This 

 uppermost dyke can be seen to pass completely through the length 

 of the quarry, and is in some places left standing above the Carboni- 

 ferous Limestone by the quarry men. As it crosses to the southern 

 end, itsvertical face is well exposed, it having been there left stand- 

 ing against the edges of the Carboniferous Limestone, beyond which 

 it is lost in its passage between two masses of that formation. 

 About the centre of the inclined floor of the quarry another vein 

 joins the above at almost a right angle, and cuts off another mass of 

 Carboniferous Limestone ; whilst, apparently joining the first vein at 

 the north of the quarry, another appears, taking a somewhat irregular 

 course in an easterly direction, and again subdividing the limestone 

 into sections. Where the working has ceased on the south, another 

 dyke of considerable thickness is present, which appears to have 

 passed across from the quarry on the opposite side of the stream ; it 

 is throughout of a deep-red colour, and yields some good samples of 

 hematite iron-ore. 



The following organic remains have been obtained from the IMar- 

 ston-road Liassic conglomerates, and from the Liassic dykes in the 

 Holwell section. 



List of Fossils from Holivell. 



Cidaris Edwardsii. 



Pollicipes. 



Claw of Crustacean. 



Pentacrinites basaliformis. 



Crania. 



Discina (fragments). 



E-hynchonella concinna, Sow. 



■■ rimosa, Ziefen. 



variabilis, SchJoth. 



subvariabilis, Bav. 



Spirifera Walcotti, Sow. 



Miinsteri (S. lata, Martin). 



Terebratula Waterhousei, Dav. (T. 

 retusa, Martin). ■ 



punctata, Sow. 



Avicula insequivalvis, Sow. 



nuda, Moore. 



Inoceramus. 



Gryplisea incurva, Sow. 

 Lima scrobiculata, Stol. 



densicosta, Quensf. 



Deslongchampsii, Stol. 



Ostrea ocreata, Besl. 

 Pecten subla^vis ? 



verticillus, Stol. 



Rollei, Stol. 



palosus, Stol. 



Placunopsis. 

 Plicatula sarcinula. 

 Opis triangularis, Moore. 

 Delpbinula reflexilabrum, Horn. 



nuda, Moore. 



Rotella macrostoma, Stol. 

 Nerinasa Hornerii, Moore. 

 Pbasianella turbinata, Stol. 

 Neritopsis la^vis, Stol 



