216 
ON THE GEOLOGY OF THE 
bird, grouse does not abound on the Snowdon range ; and 
few or none of the black game are found. 
Were advantage taken of the numerous streams which 
fall from the hills on the western side of the basin, to con- 
vey them in proper channels for the purposes of irrigation, 
immense additional produce of hay might be obtained. 
A striking instance of the want of drainage, and of the 
mischief water makes in the finest alluvial land, is. to be 
seen near Trefriew. A tract of land there, of several hun- 
dred acres, level, and of the richest vegetable mould, by 
being drenched or oversaturated by some mountain-streams, 
is now worthless and unproductive, and contaminates by 
its stagnant exhalations the otherwise pure atmosphere of 
the vicinity. A very little expense might soon, by carry- 
ing away this superfluous water, and by judicious irriga- 
tioUj convert it into one of the most productive spots of 
the basin. 
Great advantage might also be derived, for enriching 
the grass-lands of the basin, by employing more extensive- 
ly the limestone of the Orme's Head in the way of top- 
dressing. Now, however, what is employed in agriculture 
seems principally given to the tillage-lands. 
Notwithstanding the drawbacks in rearing good stock 
just described, the cattle and sheep of this basin will gene- 
rally be found as large and well formed as in the other 
districts of North Wales. 
Having already remarked that the slopes of the moun- 
tains of the Conway basin, as well as the banks of the 
rivers, and waters, are well clothed with wood, it is scarce- 
ly necessary to mention, that nearly all the varieties of 
timber are observed to grow well. Higher up in the basin, 
the south, we find, as we might expect from its high 
elevatior* birch, the alder, and the mountain-ash. But 
by the extensii"^ plantations within these few years made 
