Subjacent to the Boulder-clay. 301 



Neagh, counties of Tyrone and Antrim ; in tlie parish of Clonoe, in 

 county Tyrone ; and near Lough Eee, in Eoscommon. The Lignite 

 gives forth a heavy and j^eculiar smell whilst burning, and is 

 associated with black shales, traces of which were seen near the 

 mouth of one of the pits ; no shells were met with in any pai't 

 of the clay. 



I am indebted to Mr. Charles D. Blake, of Newton Abbot, for 

 the following detailed description of the Ballymacadam-clay de- 

 posits, the result of some borings undertaken so recently as 1 82 

 with the object of ascertaining the value of the clay for pottery 

 purposes. 



" This deposit, probably the remains of a more extensive one, 

 of which the chief part may have been removed by floods, occurs in 

 depressions, or hollows, in the grey limestone rock, from 100 to 200 

 feet in diameter, and to a depth of from 40 to 100 feet. Their 

 form is irregular, and it was not ascertained whether the sides of 

 the pockets were smooth or rough. 



"In the same locality, or near the clay deposits, are numerous 

 fissures, or ' swallow-holes,' in the Limestone rock ; they carry away 

 the surface water, and are supposed to have outlets near the river Suir, 

 about two miles below. The level of the river at Cahir is 135 feet 

 above the sea, and I should think the clay at Ballymacadam lies 

 from 150 to 200 feet above the river. There is much limestone 

 drift in the neighbourhood, but generally at a lower level than that 

 of the clay. 



" The stratification of the clay bed is tolerably perfect, and the dip 

 varies with the angle of the basin ; in some cases, as at Bally- 

 macadam Old Castle, the surface of the ground is depressed con- 

 formably with the shape of the basin, the beds appearing rather to 

 line than fill the pockets in which they occur ; but in most of the 

 other cases the surface is smooth and regular, the concavities of the 

 basin being filled with limestone, gravel, and other drift, apparently 

 of local origin, 



" The different veins or seams of clay under the gravel, forming 

 the bulk of the contents of the pocket, are numerous but thin ; one 

 or two of the seams are very pure, suitable for wliite earthenware ; 

 but they do not occur with any regularity, and therefore could not 

 be worked with profit. Some of the veins are quite white, while 

 others are of a brown, bluish, or grey color. Some borings showed 

 a very thin deposit of nearly black clay, the colour being due to the 

 presence of Lignite and Pyrites — both much decomposed. No solid 

 or hard Lignite was met with, though some of the people on the spot 

 spoke of specimens as large as trees, that had been found where 

 some small workings had been made at Ballymacadam many years 

 ago ; much of the clay contained free silica in fine particles ; the 

 seams of clay varied considerably in each pocket. Granite, supposed 

 to be the source of the plastic clay, does not appear to occur 

 nearer than the county Wexford, at a distance of fifty or sixty 

 miles." 



Subjoined are the details of a boring at Ballymacadam, also fur- 



