Page:Quarterly Journal of the Geological Society of London, vol. 29.djvu/256

 January 22, 1873.

Charles Fox Strangways, Esq., of the Geological Survey of England and Wales, 45 East Mount Road, York ; Alexander Irving, Esq., High School, Nottingham; Thomas Lidney Dickinson, Esq., of Newbold, near Chesterfield; William Bath Kemshead, M.A., Ph.D., F.R.A.S., Lecturer on Chemistry and Physical Science, Dulwich College, Hanover Villa, Thurlow Park Road, Dulwich, S.E. ; J. M'Murtrie, Esq, of the Radstock Collieries, Somersetshire ; and John Dawes, Jun., Esq., Manor Colliery, Hales Owen, near Birmingham, were elected Fellows of the Society.

The following communication was read : —

On the Glaciation of Ireland. By J. F. Campbell, Esq., F.G.S.

The following notes are founded chiefly upon observations made while travelling about Ireland in 1863 and 1872, and at intermediate dates.

A subject may be treated in two ways. If the whole of a story is known it may be told historically, from the beginning ; but if a lesson has to be learned, it is best to work back towards the unknown beginning. A great deal has yet to be learned about glaciation ; so I begin at the end.

I. Iceland and. Ireland, in different latitudes, are about the same size. In one island are ice systems, in the other none. Some Icelandic glaciers are wide as an Irish province ; and others would cover Irish counties. In Ireland lakes seldom freeze, and snow melts off the highest tops early in spring. But Ireland is glaciated.

II. Ireland. — The meridian 8° west cuts Ireland nearly in half. In the north it passes near Arrigle, the highest hill in Donegal ; in the south it passes near Cork. But the figure of the island is not square to meridians. A line drawn through Dursey Island and Rathlin, S.W. and N.E. or thereby, passes through the long axis of a diamond whose shorter axis runs from the Tuskar Rock in Wexford north-westwards to near Achill Island in Mayo. The configuration of surface within this area has relation generally to two main lines, K.E. and N.W. In Donegal, Mayo, Galway, Kerry, and Cork the largest mountain-ridges and hollows trend N.E. The course of the Shannon, the largest river in Ireland, is from the east of north. Most of the largest sea-lochs in Ireland trend N.E. and S.W. Passes in the Mourne Mountains (in Down), Carlingford Lough on the east coast, and the valley of the Erne on the west trend N.W. and S.E. The hollows which contain the river Ban and Loch Neagh and the valley of the Waterford river trend north and south. But for one great hollow running north and south a great number run N.W., and a greater number N.E. It is easily seen on any good map of Ireland that roads, canals, railways, rivers, lakes, harbours, and marshes, which occupy hollows and avoid hills, have