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destruction of extensive woods which grew along the shores, and 
the debris of which, accumulating at the outlet of the lake or swamp, 
gradually raised the level of the water. 
“« If this explanation be correct, it obviously places the date of 
construction of these islands at a very remote period. 
‘¢ In some cases, however, the only outlet from the lake was a 
stream with a rocky bed; and in such cases, the fact of the islands 
having become submerged can only be accounted for by supposing 
that the weight of*the water-soaked timber, the clay, stones, and 
other heavy materials placed on the surface, produced a gradual 
subsidence of the soft bottom on which it was constructed ; and 
the same line of reasoning will of course be applicable, in some 
degree, to all the other cases. 
‘In most instances there appears to have been nothing known 
about these islands by the people living in the vicinity. At St. 
John’s Lake, in the county of Leitrim, where portions of the islands 
were occasionally dry at very low states of the water, they appear 
to have attracted some notice; and I am told that there is a tradi- 
tion in the neighbourhood, that they were used at some remote 
period for the illicit grinding of corn, though I am not aware when 
or under what circumstances the making of meal was prohibited. 
In Loughtown Lake a portion of the island was always exposed to 
view; and it is believed by the persons in the neighbourhood that 
it was, about a hundred years ago, a place of refuge for robbers, 
who had it all fenced in, and a wooden house on it. 
‘‘ The cases that have come to my knowledge of any metal ar- 
ticles being found on these islands are very few. Mr. Coe, who 
examined the island in Leesborough Lough, mentions that there was 
found on it an iron skein or long knife, seventeen inches long, in- 
cluding four inches of that part which must have fitted into a 
wooden handle, the blade being thirteen inches long, one and a 
quarter inches wide at the handle, and a quarter of an inch thick 
at the back, tapering towards the point. 
‘«In the island in Aghakilconnell Lough, in the Eslin district, 
three iron pots were found, one of them of a triangular shape. And 
in one of the islands in St. John’s Lake were found three silver 
coins, which I have forwarded with the collection of drainage anti- 
quities, and which appear to me to be of the reign of Edward I. I 
have seen an impression taken from a coin found, as I understand, 
on a similar island, near Strokestown, in the county of Roscommon, 
