Dr. KiDD on the Mineralogy of St. David's, 89 



Not far from Carvay I met with two insulated masses, one of 

 which, bearing a very close resemblance to the mill-stone grit of 

 Derbyshire, was made up of small particles of white and reddish- 

 white semitransparent quartz cemented together by white earthy 

 felspar : the other was also a kind of grit-stone, consisting almost 

 entirely of particles of quartz, occasionally interspersed with specks 

 of white earthy felspar. Though I saw no rock in situ to which 

 these masses could be directly referred, yet as they did not much 

 differ from some of the rocks of this district, excepting in the size 

 of their component particles, and as there was net any ground for 

 supposing they had been brought there by art, they probably belong 

 to the suite already described. 



'Treginnys . 



This is a broad headland, about three miles to the south-wesL of 

 St. David's, It is frequented by trading vessels on account of a 

 fresh-water spring which rises near the edge of the adjacent cliffs, 

 beneath which is a convenient harbour. 



The general character of the rocks in the neighbourhood of 

 Treginnys is of that equivocal nature alluded to in the beginning 

 of these notes : here and there they assume the appearance of a 

 compact earthy felspar of an olive-green colour, and then probably 

 often contain epidote, compact veins and crystals of which I saw 

 in more than one instance. In one place this compact green rock 

 occurs in angular columns horizontally aggregated, and forming a 

 part of the cliffs on the north side of the harbour. The number of 

 the columns is not above eight or ten ; their form irregularly pen- 

 tagonal, and their diameter less than a foot. This was the only 



Vol. II. M 



