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 56 to be seen over a doorway in Garstang); and from them Lee states the head of hippopotamus, figured in the Natural History of Lancashire, to have been derived.

To this period we may also refer the lacustrine and peat deposits of the Isle of Man, and Ireland, which have yielded the fine skeletons of the Irish elk, now standing in the museums of Edinburgh and Dublin. The specimen in the Royal Dublin Society's collection was obtained by archdeacon Maunsell, at Rathcannon, near Limerick, in shelly marl, 1½ to 2½ feet thick under peat 1 foot thick, and above blue clay 12 feet thick or more. According to Mr. Griffith, it is in these white shelly marls, under peat, that all the skeletons of the Irish elk have been found, which agrees with what has been observed in England. (Outline of the Geology of Ireland, 1838.)

"At Milk Pond in New Jersey, countless myriads of bleached shells of the families limnæana and peristomiana, analogous to species now living in the adjoining waters, line and form the shores of the whole circumference of the lake to the length and depth of many fathoms. Thousands of tons of these small species, in a state of perfect whiteness, might be used for agricultural purposes. In one case, a perforation was made 10 or 12 feet deep, and did not pass through the mass. It forms the whole basin of the lake, and may at some future time become a tufaceous lacustrine deposit." (Lea, Contrib. to Geol. p. 225.)

Mr. Lyell's description of the deposits which are still proceeding in Bakie Loch, Forfarshire, offers an excellent type of comparison for analogous deposits of older date. The sediments in this lake are principally two beds of calcareous shelly marls, separated by a loose sandy deposit, covered by a layer of peat with trees, and resting on fine sand and detritus. The calcareous matter is supplied by springs, and in general is of a soft friable nature; but near the springs it is solidified, and receives the title of "rock marl" It is principally to the vital functions of limnæa, cyclades, and charæ,