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78 the Alleghanies, shells from the Gulf, and obsidian (perhaps porphyry) from Mexico." Fair representations of the sea-cow or manatee are found a thousand miles from the shores inhabited by that animal, and shells of the large tropical Pyrula perversa are met with in the tumuli round the great lakes, two thousand miles from home.

In Central America thousands of jadeite implements occur, but no locality for native jadeite has yet been discovered.

On the whole, however, flint was the stone most frequently used in Europe; and it has had a much more important influence on our civilization than is generally supposed. Savages value it on account of its hardness and mode of fracture, which is such that, with practice, a good sound block can be chipped into almost any form that may be required.

In many cases, blocks and pebbles of flint, picked up on the surface of the ground, were used in the manufacture of implements; but in others much labour was spent in obtaining flint of good quality. A good illustration of this is afforded by the so-called Grimes' Graves, near Brandon, which have, by the kind per- mission of Mr Angerstein, been explored by Canon Greenwell; who has shown them to be excavations made in the chalk for the purpose of obtaining flint. They are 254 in number, varying in diameter from 20 to 60 feet, placed irregularly, generally about 25 feet apart, and occupying rather more than 20 acres. They have been filled up, and are now indicated by shallow depressions, but Canon Greenwell has proved that the pits originally went down to a depth of about 40 feet, when they branch out into passages, often communicating with one another. On the east side is a mound, apparently consisting of chalk taken from the first pit; after which it would seem that when a new pit was dug, most of the material was thrown down the old shafts, which were thus filled in, to