On some Peculiar Markings occurring occasionally on the Broken 

 Surfaces of Flints. By N. T. Wetherell, Esq., M.R.C.S., of 

 Highgate. 



The appearances to which I call attention consist of a series of 

 very fine, variously-curved lines, generally placed one above the 

 other, the series being sometimes branched. The lines are about 

 the thickness of a hair, and often so closely set, that, in the space of 

 an inch, as many as fifty have been counted. They vary in form from 

 circular to an oval, and I have occasionally seen some which have been 

 waved. It sometimes happens that these lines are very irregularly 

 grouped together, as if a small handful had been taken up and 

 sprinkled over the surface of the flint. They for the most part 

 assume a dark colour ; and I have two examples which are highly 

 ferruginous. I was disposed at one time to consider these markings 

 to be of organic origin, but not having detected any structure under 

 the microscope, and having also observed similar appearances in dried 

 paint which had been spread upon wood, I think it is not improbable 

 that they are inorganic. The flints which I have examined are from 

 the gravel-pits in the vicinity of Highgate ; and I shall have much 

 pleasure in depositing some specimens in the Museum of the Geolo- 

 gical Association. 



I will now briefly advert to some appearances in broken flints, 

 which are clearly due to fracture, and which I consider bear some 

 slight analogy to the markings above described. 



If the broken surface of a flint which has been smartly struck 

 once or twice with a hammer be examined, there will be detected, 

 in some instances an arrangement of curved lines. On viewing these 

 appearances one is naturally led to contemplate in what manner they 

 are produced. May it not be due to the tendency of silex to assume 

 a circular form under certain conditions ? 



