) 
220 
Mr. Weaver on the 
discovered and wrought a few years since. It was a contempora- 
neous vein of quartz, ranging and ramifying in clay slate, and bear- 
ing galena, white lead ore, blende, iron pyrites, and copper pyrites. 
Of the copper ore, twenty-four tons were shipped, and of the 
galena, it is said, a few hundred tons. The workings extended 
about thirty fathoms in length, and went down in the deepest part 
about twenty-four fathoms; but having no command of level, nor 
sufficient water to impel machinery, they were discontinued. 
II. Transition Tracts, 
§ 119. In the whole field of our inquiry, I have not met with 
any rocks that possessed decidedly the character of transition forma- 
tions, except on the coast of the county of Dublin. They appear 
there in detached portions, comprehending the islands adjacent to 
the shore ; as at Portrane headland, a small patch at Loughshinny, 
and the coast extending from the south of Skerries past Balbriggan, 
to the Del van stream on the north, which divides the county of 
Dublin from that of Meath. 
§ 120. These transition tracts are mostly bounded by the floetz 
limestone formation; and as the rocks of both classes exhibit upon 
this coast relations deserving particular attention, I shall, in the 
proper place, enter into a full description of the portions occupied 
by them respectively. By following this plan, we shall obtain the 
advantage of tracing in uninterrupted succession the relations of the 
primary, transition, and floetz rocks, in immediate connexion with 
each other ; and the survey of the coast of the county of Dublin 
will be completed. The remainder of the great limestone field may 
then be treated in a more general manner. 
