Knowies—Flint Implements from North-East of Ireland. 4387 
ordinary flint factories like those I have explored at Ballintoy, Port- 
stewart, and Dundrum. If the worked flints of the raised beach are 
of neolithic age, it is therefore a strange fact that all those objects, 
which are admitted to be of that age, are absent. 
The worked flints from the raised beach have a thick crust, 
mostly white, but sometimes reddish, having been stained before 
inclusion in the gravels; while arrow-heads, scrapers, and other im- 
plements of undoubted neolithic age, which are found in various parts 
of the country, are only very slightly changed. 
On the surface of the crust there is a porcellanous glaze, so hard 
that it cannot be scratched with a knife; but, when broken, we find 
that the part beneath the surface corresponds very closely, both in 
appearance and hardness, with the broken edge of a piece of common 
delf. J have several flakes and cores which I found 7m stu in the 
gravels which have had the hard glazed surface worn off, especially at 
angular parts, such as the ridge made by the removal of two flakes, 
leaving the rough and more porous part beneath the surface exposed. 
I can prove, from the action of the waves at the present time, that 
this wearing away of the glazed surface was caused by crusted flint 
haying been rolled about by the waves. If we pick up some of the 
pieces of ordinary delf which find their way to the sea-shore near 
towns, we will find that, from having been rolled about by the waves, 
the glazed outside has been worn off the angular ridges frequently 
found about the bottom and rim, leaving the rough interior exposed, 
just as we find in the case of the flints. When those flints which 
have had the glazed surface worn off are compared with the pieces of 
waterworn delf, the likeness is very striking and convincing. This 
shows us that the thick delf-hke crust had been formed on the 
worked flints, and that they had been rolled about by the waves of 
the sea till the hard glazed surface was in some parts worn off, before 
being inclosed in the gravelly formation of the raised beach. The 
worked flints are therefore older than the formation in which they are 
included. 
THe Incrustation.—When a flake or other incrusted flint is 
broken, we find the crust to be of considerable thickness. J have 
found it, in some cases, to occupy fully two-thirds in thickness of the 
substance of the flake. The crusted part does not break with the 
smooth even fracture of the flint, but is rough and hackly. It is the 
weathered part of the flint, and must have been formed by exposure 
to the atmosphere, or when only so slightly covered that air and 
water had free access. I have paid attention to the subject for some 
time, and I find that the weathered crust has not formed on flints 
buried in the boulder clay, nor in the interglacial gravels which are 
covered by boulder clay. Neither has it formed on flakes and scrapers 
which I found imbedded in the old surface layers of the sandhills 
near Ballintoy, Portstewart, and Dundrum; while flints found on the 
surface near those places are more or less whitened and glossy on the 
surface. I have also obtuined arrow-heads and other manufactured 
