TRANSITION ROCKS. 137 



Nos.29. Vein-stone of Quartz, impregnated with red Oxide of Iron, 

 and containing white Steatite, from Tincroft. 

 So. From the high-road near Tincroft. This is a very tough rock, 

 and very fine-grained : it appears to be a variety of Green- 

 stone similar to NO. 10. 

 31 • Killas, marked with dark-coloured spots, from the side of the 

 road to Cambourn, a little westward of the last. 



32, Killas of a light-grey colour, from St Anns. 



33. From Beacon Hill, a conglomerate formed of the debris of 



Granite, very similar to some varieties of Sandstone. 

 34, 35. Granite from the Land's End. 



36, 37. Hornblend-Rock from Botallock, a curious, little, but valuable 

 mine, on the north side of the Peninsula, near the ex- 

 tremity. 

 Cockle, massive Tourmaline, from the same place. 

 Specimens from the junction of the Granite and Killas, at St 

 Michael's Mount. 

 42, 43. From the shore near Penzance : these I consider to be Killas 

 of a very tough and compact variety, they are found very 

 near Granite, or some similar rock, which presented some- 

 thing so peculiar in the aspect, that I cannot help recom- 

 mending it to the attention of geologists. 

 Serpentines from the Lizard. 

 47- Hornblend-Rock, which forms the basis on which the light- 

 houses of the Lizard stand. 

 48. Clay-porphyry, near Trewithin. 

 49- Granite, with a vein of Tin, St Stephen's. 

 50. Conglomerate of Quartz and Granular Talc, from the same 



place. 

 52 - Phosphate of Lime and crystallised Talc, in Granular Talc, 



from Stoney Gwins. 

 53 - Killas from a quarry between Bodmin, and the race-course of 

 that town. This substance is very soft, but well adapted 

 Vol. VII. S for 



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