FOUND IN THE LANOASHIRB COAL FIELD. 1181 



to it.* The vein varies in thickness from fourteen to twenty 

 inches. It is wider in its upper than in its lower part, and 

 is filled with white crystallized sulphate of barytes, exter- 

 nally discoloured by a little peroxide of iron, and cleaving 

 very freely in a vertical direction. On the walls of the 

 fissure are also seen small crystals of iron pyrites. Enve- 

 loped in the barytes are portions of the neighbouring 

 sandstone rock, much altered in structure, and entirely sur- 

 rounded by it. The vein could not be traced upwards so far 

 as to prove satisfactorily whether or not it went through iito 

 the till; but, from the view afforded at the bottom of the 

 quarry, it certainly seems to extend a little higher than the 

 top of the sandstone rock. 



The walls of the fissure, although once composed of a 

 laminated sandstone, as is evident from the lines of bedding 

 still seen in some portions of it, are now of a highly crystal- 

 line structure, and have an imperfectly developed columnar 

 arrangement of their particles, like basalt. On the north- 

 west of the vein the quarry has been little worked, so that 

 it is not possible to see how far the rock is altered ; but on 

 the south-east the whole of the stone in the quarry presents 

 an unusual degree of hardness, and for fifteen yards is \ery 

 visibly altered. There are several smaller veins of sulphate 

 of barytes traversing the rock, showing little heaves like 

 the large one, and running in a similar direction.! Many of 



* The veins of barytes at Anglezark, worked many years ago, and 

 described in a paper read before this Society by the late Mr. James 

 Watt, jun,, F.R.S., and printed in voL ii, (1st series) of the Society's Me- 

 moirs, are of a very similar character to that now described. These also 

 occur chiefly in the rough rock, and proceed from a fault running from 

 S.S.E. to N.N.W., in a direction 60" east of north. They contained sul- 

 phurets of lead and zinc, neither of which have been, to the author's 

 knowledge, met with at Grimshaw Delph. All the veins of barytes which 

 he has observed in Lancashire and Yorkshire, have a direction from about 

 N.E. to S.W. 



t Since this paper was read the author has again visited the quarry, and 



