THE FRACTURE OF FLINT. 



fields are covered with nuclei, flakes, etc.; and implements 

 made here, and easily recognizable by the peculiar colour, 

 have been found in various parts of France, and even, it 

 would seem, in Belgium. I have in my collection a block of 

 Pressigny flint, from which a flake more than twelve inches 

 in length has been struck. The large nuclei of this form, 

 which from their shape are known as " livres de beurre," have 

 excited a good deal of discussion. They are generally from 

 eight to thirteen inches in length, shaped more or less like a 

 boat, with a broad butt at one end, tapering gradually to the 

 other. The form has been attained by a succession of lateral 

 chips, at right angles to the longer axis, while generally one 

 or more longitudinal flakes have also been removed. 



Many of the flint flakes were certainly never intended to 

 serve as knives, but were worked up into saws, awls, or arrow- 

 heads. Savages use flint or chert in this manner, even at 

 the present day; and the Mexicans, in the time of Cortez, 

 used precisely similar fragments of obsidian. 



The operations of modern gun-flint makers give us a very 

 clear insight into the mode of manufacture of ancient flint 

 implements, and the process is one of considerable interest. 



If we take a rounded hammer, and with it strike on a 

 flat surface of flint, a conoidal fracture is produced, the size 

 of which depends, in a great measure, on the form of the 

 hammer. The surface of fracture is propagated downwards 

 through the flint, in a diverging direction, and thus embraces 

 a cone, the apex of which is at the point struck by the ham- 

 mer, and which can afterwards be chipped out of the mass. 

 Flint cones, formed in this way, may sometimes be found 

 among heaps of stones broken up to mend the roads, and have 

 doubtless often been mistaken for casts of fossil shells. 



If a blow is given, not on a flat surface, but at the angle 

 of a more or less square flint, the fracture is at first semi- 

 conoidal or nearly so, but after expanding for a short distance, 



