596 Extracts from the Minute Book of the Geological Society. 
within the copper of the vein ; but this was only conjecture, for in 
whatever quantity it might then have been encountered, it was 
avoided as much as possible, and the many tons landed were 
removed as rubbish to make way for the miners. One great cause 
of the abandonment of the mine was the pecuniary difficulty 
occasioned by the war. Commercial intercourse, particularly the 
high insurance to Bristol, was too expensive for the then state of the 
mine, viz. working upon a new and shallow part of the vein. Since 
that period lands having risen much in value, the proprietors have 
been unwilling to injure the surface of their grounds by the admis- 
sion of workmen who might trespass upon and disfigure their estates. 
The mine in question is on the demesne of Mr. Herbert, and is one 
of the most picturesque spots about the celebrated lake of Killarney. 
It is situated at the head of the Great Lake, which, being thirty-seven 
fathoms deep, is navigable for boats of any burthen for five miles to 
the head of the river Laun, a considerable stream, as broad as the 
Thames at Windsor; this is also navigable, though not to any 
useful extent, nor at all times, owing to some shallows which might 
easily be deepened. The fall in the ten miles to the sea is only 
thirty-seven feet. Castlemain Bay, the port, is a safe harbour, 
though there is a bar at the entrance of it. This natural navigation 
might be improved at no great expense, and it is so desirable for 
the commercial and agricultural purposes of the inhabitants of a 
district not only extensive, but valuable for its oak woods as well as 
its mines, that it has become a national object to clear the bed of the 
river, and the Government having offered to defray one-third of the 
expense, the landed proprietors and others have agreed to raise 
subscriptions sufficient to carry it into execution, so that the business 
only requires to be set about. 
The copper mine of Ross Island, in the neighbourhood of Mucrus, 
