90 NATURAL SCIENCE. February. 



gravels were deposited, since their deposition has never disturbed the 

 underlying beds. The glacial deposits, on the other hand, may contain 

 anything older than themselves, down to and including the Chalk. 



Below the Glacial beds is the Forest Bed series. Into a full 

 description of this we need scarcely enter here, suffice to observe that 

 every one now knows this is not a Forest Bed at all, but was deposited 

 in the estuary of a river, which during its history — probably like many 

 others — fluctuated in salinity. When we first meet it, it is fresh, then 

 a N.E, subsidence asserts itself and estuarine conditions obtain, but 

 only for a while, and the last we see of this interesting link with the 

 Pliocene period is that its waters are running fresh. During many 

 parts of its life, at least, it was a powerful stream, sometimes cutting 

 through the underlying Weybourn Crag. The latter, when present, 

 rests upon the Chalk. Both in the Weybourn Crag and the Forest 

 Bed, when they rest upon an impermeable sub-stratum, there is often 

 developed a very heavy iron pan. One of these occurs in the Forest 

 Bed, and is distinguished from the rest by the number of large 

 mammalian bones it has preserved, from which fact it has long been 

 known as the Elephant Bed. There is another important feature 

 about this bed which perhaps has not been publicly noticed, or at any 

 rate I do not know that any one has drawn attention to the fact, 

 although many have noticed it, and that is, its property of imparting 

 to the contained fossils an amethystine tinge. This colour in silica is 

 attributed to manganese, but as there is so much of this metal in most 

 gravels without this coloration, it may be supposed that in the form 

 of manganese dioxide, in which it occurs in ordinary river deposits, it 

 does not so colour ; but that as another oxide it may ; and possibly the 

 original dioxide of this pan may have been so altered, and thus colours 

 not only the bones, but the contained flints. When the iron is the 

 more active, we get the flints of a brown colour, with various 

 amethystine tinges ; when the reverse is the case, we get the flint 

 assuming a beautiful black, with the same amethystine hue pervading. 

 This staining process is often very deceptive ; at first sight, a flint 

 appears quite fresh, but the moment the edges are abraded the fact 

 is revealed that the flint is very much altered. As might be expected, 

 there is every intervening stage of alteration present, but all are 

 characterised by this amethystine tinge. This peculiarity may at 

 first appear unimportant, but when we remember that it is character- 

 istic of the bed under consideration, it becomes of very great importance, 

 as when present it enables one to fix the horizon of a flint or bone 

 after it has been washed out of its original matrix. 



To come at last to the main subject of this paper. Recently 

 in working this " Elephant Bed " for bones, I was delighted, 

 after breaking away some eighteen inches of the iron pan, to 

 see sticking out what appeared to be an unmistakable worked flint. 

 I called my wife to see it in situ, before it was removed, since I fully 

 realised the opposition that would be raised by a certain section of 



