676 
Agriculture of North Wales. 
the river Trywerin to Llaniichlyn, it is ngain found at Llanfachratb, 
Braich y Bedw, Bluenaw, Hengurtucha, Caer Ynwch; and last of all, 
Bwlch foch, near Cader Idris. Other places where this grey lime- 
stone is fouiul, in a line jiarallel with the former, are Rhiwaedog, and 
at the other side of tiie Berwin at Rhiwarth, at Bryn Mclyn, Cwym 
Hyfed, Bwlch y Groes, and Cwm Tylyddian, near Llanymowddy.' 
It is also found at Craig y Glyn, and a parallel band to the 
Bala limestone passes through the Berwins, called by geologists 
the Hirnant limestone. Knowing the value of limestone in 
moorj districts, I was anxious to obtain specimens of the various 
strata of limestone just described, but in consequence of taking 
the new instead of the old road from Bala to Llangynog, I entirely 
missed seeing the Hirnant Bands; I however got my guide to 
take me to the Bala series, and I collected some specimens from 
a heap of broken limestones that lav beside an old limekiln ; the 
guide informed me that the country people had ceased to use the 
Bala limestone for many years; indeed the broken stones appeared 
as ihouffh they had been expoi^ed to the weather some years ; the 
kiln also appeared to have been disused for a long time; a 
specimen I have since analyzed, and I find that, when calcined, 
it yields 49 per cent, of lime.* I have not had an oppor- 
tunity of analyzing the impurities, but they apparently consist of 
silica and alumina. This limestone burns to a grey or brownish 
colour, and is too impure to be used for building purposes ; but 
the country people say it is stronger for manure than white lime ; 
if this is really the case, doubtless some of the impurities consist 
of substances forming the earthy constituents of plants. As lime 
is generally applied to boggy land, it is not at all unlikely that 
the silica is the principal additional fertilizing ingredient. That 
the Rhiwlas, Glyn Diffvvys, and Bala series of limestones are 
overlooked at the present day, I had ample means of noticing; 
amongst other places I may mention that I found lime composts 
preparing 6 miles from Bala on the Festiniog road, the lime for 
which had been brought from Gwerclas,| near Corwen, a distance 
of 16 miles, although the Glyn Diffwys beds were absolutely 
within a couple of miles from the spot. The Bala and analogous 
limestones can be, and are, burned with turf, which is a great 
advantage, as peat is almost always to be found in abundance in 
its vicinity. 
Lime being procurable, the mountain farmer may safely com- 
" The specimen alluded to above had the appearance of ordinaiy car- 
bonilerous limestone, bein^ of a crey colour and crystalline. It consisted 
of 12 per cent, of earthy matter insoluble in acids, and 88 per cent, of car- 
bonate of luiie. 
t At Gwerdas there is an insulated lime-rock, which affords the ordinary 
wliite lime. It is burned with coals brought from Ruabon: the present 
price is Hd. per bushel at the kiln. 
