350 ■ Synoptical Table of Minerals and Fossils 



colour; with light-coloured crystals of felspar, and fragments 

 of crystalline quartz, in a boulder. — 6. Porphyry: a paste of 

 felspar of a brown colour, with numerous embedded crystals of 

 black hornblende and crystals of felspar. This is one of the 

 old porphyries of Dr. Maculloch. — 7. Basalt : black, with 

 cavities occupied with zeolite and other minerals peculiar to 

 the trap rocks. — 8. Basalt : very similar to that kind called 

 Rowley rag, from near Dudley ; the outside of the boulders is 

 the colour of iron rust. They are very hard to break ; the 

 inside is of coal-black colour. Very common. — 9. Basalt: horn- 

 blende and felspar, with minute crystals of hornblende or augite. 

 This appears to be a part of a basaltic column : the meeting of 

 the two plane surfaces shows an angle of 95°. — 10. Basalt: 

 amorphose hornblende. — 11. Basalt: compact felspar, with 

 minute crystals of hornblende or augite. — 12. Basalt: clink- 

 stone. — 13. Basalt : compact felspar, with a fine laminated 

 structure. — 14. Compact felspar of a coal-black colour, with 

 numerous crystals of hornblende. Basalts Nos. 9, 10, and 14. 

 all have iron in their composition, as the magnetic needle tes- 

 tifies : the needle is never active before No. 10. Compact 

 felspar : in large and small boulders, with crystals of felspar 

 embedded : the stones are in a state of decomposition ; the 

 paste of them is much like a decomposing basalt brought 

 from Ireland, in the London Geological Society's collection. 

 Felsparthic breccia ? : in boulders apparently composed of the 

 preexisting materials of granite subsequently recompounded : 

 these consist of quartz and mica cemented into a felsparthic 

 paste, different from the porphyries, the minerals having lost 

 all crystalline form. Lydian stone : in boulders, reticulated 

 by veins of milk-white quartz, some as fine as hairs ; and 

 these are pleasingly contrasted by the glossy black colour of 

 the stone : very numerous. 



Conglomerates or Breccias. — 1. A very hard crystalline 

 paste of a beautiful deep blue colour; with angular fragments 

 of white quartz, from the size of peas to that of walnuts, 

 regularly disseminated throughout the mass. — 2. Small 

 rounded black and brown flints, with a boulder of porphyry, 

 united with finely triturated quartz in a highly crystalline 

 siliceous cement. — 3. Angular fragments of the size of the 

 former, of a crystalline and granular brown quartz ; cemented 

 firmly together by a black and hard crystalline paste, appa- 

 rently hornblende or augite. — 4. Angular fragments of milk- 

 white quartz, from the size of a pin's head to that of a pea, 

 cemented by a red crystalline paste. — 5. Rounded fragments 

 of white quartz, the size of peas, mixed with quartz sand, both 

 rounded and angular; the whole firmly united into a reddish 



