Lough Mask and Lough Corrib were, in fact, already connected, with water flowing through caverns underground, but apart from providing a surface link, a canal with locks was needed because one lake is lower than the other. The difference varies with rainfall and season, but Lough Mask can be 1.8 metres higher than Lough Corrib. The canal was dug, but it never filled. The project was a failure, and when water was fed into it simply drained away to disappear into the porous limestone. The failure was not due to an error or ignorance, but the money needed to finish and seal the canal was not forthcoming. £82,285 had already been spent, and with the arrival of rail, local landowners, who had been expected to benefit, lost interest in throwing good money after bad.
The area between Saint Patrick’s Reek in Mayo and the wilds of Connemara is rich in history and its valleys, lakes and mountains are among the most spectacular in Ireland. Tom Kennedy reports how the rocks are adding value to the attractions.
An outline chart of the geology between Clew Bay and Connemara
Carboniferous limestone Deposited in a warm tropical sea about 300 to 454 million years ago. The Clew Bay complex An assortment of greatly altered Silurian rocks. Silurian Formed about 410 to 440 million years ago from sands and mud deposited in the Iapetus Ocean from an ancient continent, Laurentia. Caledonian Granite Magma welled up and slowly solidified below the surface to form granites, which have since become exposed by weathering away of the covering rocks.. Ordovician Deposits laid down between about 450 and 490 million years ago at a time of intense volcanic activity. Ordovican volcanic rocks As continental plates collided, pushing the ocean floor under, this area was in a ring of volcanoes. Dalradian Precambrian rocks, among the oldest in Ireland, at over 550 million years.
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efore anyone thought of creating a western rail corridor, there was a grand plan to link Ballinrobe to Galway. Vessels were already crossing Lough Corrib, and all it would take was a 6.4 km long canal to allow them continue their journey up by Cong to Ballinrobe and the head of Lough Mask.
Both lakes are vast, Lough Mask is sixteen kilometres long and four wide, and the prospect of linking the two was highly attractive, so in 1840 work began on building a canal. Construction continued for five years with an army of diggers and shovelers being paid between ten pence and a shilling a day.