438 Proceedings of the Royal Irish Academy. 
flint objects from peat bogs having their surface dull and fresh, as if 
only newly made. 
The incrusting process would, no doubt, be largely influenced by 
the nature of the flint, some kinds containing more impurities than 
others, and also by atmospheric conditions. The crust might there- 
fore form on the flints of one district more quickly than on those of 
others; but, in county Antrim, the quality of the flmt from which 
the worked flints of the raised beach were formed must, in many 
cases, have been similar to that from which our arrow-heads and 
scrapers were made; and supposing both sets to be of the same age, 
the conditions as to climate must often have been the same for both. 
Might we not, therefore, reasonably expect that if not generally, at 
least frequently, we would find arrow-heads and scrapers as deeply 
crusted as the flints of the raised beach. We find, however, that such 
is not the case; and that even arrow-heads and scrapers found on the 
surface at Larne and Island Magee, quite close to where the whitened 
flints of the raised beach are taken up, are frequently without the 
slightest trace of weathering. I think it will be taken for granted 
that I speak from sufficient experience, when I say that I have been 
collecting flint implements for over twenty years, and that my collec- 
tion of flint objects of neolithic age exceeds 6000, fully 2000 of which 
have been collected by my own hands. Yet in examining all these 
objects, I find no change on the surface that can at all be compared 
with the great change that has taken place on the surface of the flints 
from the raised beach. 
We meet sometimes with arrow-heads which have the surface 
whitened, as, for example, those found at Portstewart, but, if broken, 
the crust will be found to be very thin. We find other arrow-heads, 
again, whitened all through; but if we break them, we see that the 
substance has still the close texture and even fracture of flint ; and if 
the whiteness is the result of a change caused by exposure to the 
weather, and not owing to the flint partaking of that colour at first, 
then the change must be in a very early stage as compared with that 
which has taken place on the flints from the raised beach. 
The crust on paleolithic implements is frequently spoken of as a 
calcareous incrustation; but the crust of the flmts from the raised 
beach seems to have nothing calcareous about it, as I haye tried acids 
on many specimens, and found no effervescence. I have not had a 
chemical examination made; but I believe it will be found that the 
weathered crust is a silicate of some kind. 
In some of the flints the crust has a banded appearance, almost like 
an agate. Fig. 9, Pl. xxim., shows the section of a broken flake, 
where the crust is divided into two by a band of closer texture passing 
along the middle. In Fig. 10, Pl. xxm., we have the section of an 
implement which has been broken, where five bands are seen, three 
of which are light-coloured, and separated by two other bands of 
closer texture, approaching in appearance the unaltered flint of the 
interior of the implement. I do not know what these lines of closer 
