Page:Memoirs of the Geological Survey of Great Britain, Volume 1.djvu/379

366 and Mr. Hamilton, had remarked on the fossils it contained. More recently, Mr. Oldham has given lists of Irish drift fossils. (For the papers referred to, see 'Proceedings of the Geological Society of Dublin.') But by far the most valuable data on the fossil contents of the drift in Ireland—data which for importance as bearing on the questions of its origin and history, can be compared only with those collected by Mr. Smith and Mr. Lyell—have been brought together during the researches of this survey, by Captain James, R.E., Chief Geologist for Ireland, and will be made known in detail in the course of the Survey Reports. In Wales the fossils of the glacial beds were made known by Mr. Trimmer, who has done much to thrown light on their history. To him we owe the information respecting the presence of existing shells on the summit of Moel Trefaen. Mr. Strickland has published in the Geological Proceedings valuable and critical observations on the fossils in the Isle of Man beds, further information on which has been recently communicated to the Geological Society by the Rev. R. G. Cumming. The observations of the Rev. Mr. Landsborough (Geol. Proc., vol. iii. p. 444), on pleistocene beds in the east of Scotland are very valuable, from their minute accuracy, a quality without which no natural-history statements on this subject can be received as of any authority. To complete this brief notice of the zoological literature of the drift, we may enumerate Capt Bayfield's and Mr. Lyell's papers on the fossils in the Canadian beds, published in the Geological Transactions, the figures of drift fossils in Hisinger's 'Lethæa Suecica,' the papers of Dr. Forchhammer, the lists in Mr. Lyell's 'Travels in North America,' and the account of the fossils of the Russian drift, in Sir Roderic Murchison's great work on Russia, all containing data of the most accurate and valuable kind.

The British formations of the glacial epoch present themselves in the form of partially stratified, or often entirely unstratified beds of clay, marl, sand, and gravel, varying greatly in different localities; in many places charged with rounded boulders. Generally the clays and marls are inferior to the gravels and sands. They are to be met with in many parts of both east and west of Scotland; on both sides of the north of England; in Wales; through a great part of Ireland, and in the Isle of Man. These beds attain various degrees of thickness, forming in places cliffs more than 100 feet high, and occupying various elevations above the sea, from 0 to more than 1000 feet. When carefully examined, most of them are found to contain fossils, mostly marine testacea, usually scattered, rolled and broken, but in particular localities, entire and undisturbed, and presenting undoubted evidence of their having lived and died on the spot. In such places they are abundant; when rolled and broken, usually dispersed, and in no great plenty.

I have personally examined these fossils in situ in most of the localities