The Hon. H. G. Bennet on a Whin Dyke. 103 



tion diminishes in degree as the distance from the dyke increases, 

 and it is about 20 feet before the limestone acquires its perfect pro- 

 perties of burning into good lime. The same thing is observed in 

 both the strata of limestone. The stratum of what I shall term a 

 species of tuf, composed of felspar and carbonate of lime, is indu- 

 rated as it approaches near to the whin, and it then resembles in 

 structure and colour the whin itself; it is much fuller of joints near 

 the dyke, than at a distance from it. In no case did there appear to 

 be a complete junction of the whin with the limestone, or with 

 the tuf; but there is invariably a small fissure, that seems to sepa- 

 rate them to a great depth, on the edges of which the limestone 

 sometimes assumes a sparry structure, and is in some places con- 

 siderably mixed with pyrites. In one part of the dyke a piece of 

 the tuf is enveloped in the middle of the whin ; this fragment is 

 about 60 feet in length, and 2 feet in breadth at its broadest part, 

 and the two ends terminate in points. 



The following is a section of the strata, obtained from the infor- 

 mation of the proprietor of the lime works. feet. 



Limestone 22 



Tuf 39 



Black metal, argillaceous slate 27 



Limestone 16 



Slaty and micaceous sandstone and black metal 27 

 Coal, a thin seam. 



That part of the strata, which the workmen called argillaceous, 

 I had not an opportunity of examining, at least where it was in 

 contact with the whin, it being under water. Neither could the 

 coal be seen, as it is at too great a depth. 



The strata dip about one yard in six to the south ; but their ge- 

 neral inclination in this district is to the east and north-east. 



