SWEET PASTURES OF THE MOUNTAIN LIME-STONE. 251 



less full of organic remains. In some 

 localities, it occurs in beds of vast thick- 

 ness — (Derby and Yorkshire) — while 

 in others — (Northumberland) — it is di- 

 vided into numerous layers, with inter- 

 posed sand-stones and beds of shale, and 

 occasional thin seams of coal. 

 Extent. — The greater portion of the counties of Derby and Northumberland 

 are covered by this formation, and from the latter county it stretches along the 

 west of Durham through Yorkshire as far as Preston, in Lancashire — forming 

 the mountains of the well known Pennine chain, which throw out spurs to the 

 east and west, and thus present on the map an irregular outline and varying 

 breadth of country. In Scotland these rocks cover only a small portion of the 

 county of Berwick, immediately on the Border; but in Ireland, almost the en- 

 tire central part, forming upwards of one-half of the whole island, is occupied 

 by the mountain lime -stone formation. 



Soil. — From the slowness with which this rock decays, many parts of it are 

 quite naked ; in others, it is covered with a thin light porous soil of a brown 

 colour, which naturally produces a short but thick and sweet herbage. Much 

 of the mountain lime-stone country, therefore, is in natural pasture. 



Where the lime-stones are mixed or interstratified with shale beds, Avhich de- 

 cay more easily, a deeper soil is found, especially in the hollows and towards 

 the bottom of the valleys. These are often stiff and naturally cold, but when 

 well drained and limed produce excellent crops of every kind. In Northumber- 

 land, much of the mountain lime-stone country is still in moor-land, but the ex- 

 cellence of border farming is gradually rescuing one improveable spot after ano- 

 ther from the hitherto unproductive waste. In Yorkshire and Devonshire also 

 improvements are more or less extensively in progress, though, in all these dis- 

 tricts, there are large tracts which can never be re-claimed. 



E. — Old Red Sand-stone or Devonian System. 



17°. Old Red Sand- ? 500 to The upper part of this formation con- 



stcme. I 10,000 ft. sists of red sand-stones and conglomer- 



Old Red Conglomerate. ates (indurated sandy gravel), the mid- 



Corn-stone and Marls. ^^^ of spotted, red and green, clayey 



Tile-stone. marls, with irregular layers of hard, of- 



ten impure and siliceous lime-stones 

 (cornstones) likewise mottled, and the 

 lowest of thin hard beds of siliceous 

 sand-stones, sometimes calcareous, mot- 

 tled, and splitting readTly into thin flags 

 (tile-stones). 

 Extent. — Though occasionally of vast thickness, the old red sand-stone does 

 not occupy a very extensive area in our island. In the south of Pembroke it 

 forms a tract of land on either side of the coal-field — surrounds on the north and 

 east the coal-field of Glamorgan, and immediately north of this county covers a 

 large area comprehending the greater portion of Brecknock and Hereford, and 

 part of Monmouth. A small patch occurs in the Isle of A nglesey, and in the 

 north-eastern corner of Westmoreland — but it does not again present itself till 

 we reach the western flank of the Cheviot Hills. It there appears on either 

 side of the Tweed, and extends over a portion of Berwick and Roxburgh to the 

 base of the Lammermuirs. On the north of the same hills it again presents it- 

 self, and stretching to the south-west, forms a considerable tract of country in 

 the counties of Haddington and Lanark. On the north of the great Scottish 

 coal-field it forms a broad band, which runs completely across the island in a 

 south-western direction along the foot of the Grampians, from Stonehaven to 



