Dec. 7, 1888.] 



SCIENTIFIC NEWS. 



5§7 



which there was so much worn away that it was converted 

 into the peculiar rounded form of the pebble; those 

 pebbles were nothing but water-worn flints. Here 

 was a case where they were obliged to fall back upon 

 observation. Nobody could watch for himself the 

 actual wearing of the actual flints and pebbles, but by 

 examining all those cases they might convince themselves 

 that without doubt the flint-pebbles were merely angular 

 flints that had been worn and rounded. In that way 

 they arrived at the conclusion that those sub-angular and 

 rounded flints, which occurred in the gravels beneath 

 and around London in such great abundance — that those 

 flints were nothing but flints from the chalk which had 

 undergone this process of rounding and rolling by the 

 action of the water. It was true that their colours 

 were very different in many cases from the colours 

 of ordinary black and grey flints, but, as he had 

 pointed out to them, the colour depended upon the 

 very minute quantities of foreign substances in it. He 

 had shown them how small a quantity of gold would alter 

 the colour of a great mass of water, and it was equally 

 true that a minute quantity of iron combined with oxygen 

 would alter the colour of a great mass of flint ; and so 

 far as the chemist was able to find out, there was very 

 little difference indeed between those flints which were 

 converted into a brown or red tint and those which 

 retained their original black or grey colour. If 

 any doubt existed as to these pebbles having come 

 originally from the chalk, it would be dissipated by the 

 fact that they often found shells and fossils, to which he 

 would have to refer, in the middle of those rounded 

 pebbles ; and in all cases the shells and other fossils 

 found in the gravel flints were the same as those found in 

 the chalk flints, so that, after examining a great number 

 of cases of that kind, they could not doubt for a moment 

 that the flints which were found in gravels had been 

 once flints imbedded in chalk. That being the case, 

 then, they might dismiss the question of the gravel flints. 

 These were once imbedded in chalk. They had merely 

 been washed out and left behind on account of their 

 hardness, while the chalk had been washed out and 

 dissolved, and the flints had been gradually rolled into 

 rounded forms, passing through the condition of sub- 

 angular flints into the condition of pebbles. 



Let them, then, go to the chalk itself, the original source 

 of the flints, and inquire howtheflints occurred inthechalk. 

 They were all familiar with the chalk which appeared at 

 so many points around London, points which they must 

 all have visited. They had, no doubt, all seen the chalk 

 pits on the downs, and in these days of easy transit 

 probably all must have seen the chalk-cliffs in the Isle of 

 Wight or along the south coast of England, where there 

 were beds of chalk with layers of flint lying in them. They 

 must all be familiar appearances of those chalk strata. 

 Now, if they went to the chalk downs or to the chalk cliffs, 

 and examined either the openings in the chalk or saw the 

 cliff where the chalk strata were exposed, they would be 

 able to observe the way in which the flints occurred. All 

 who had visited the chalk cliff or bed must have noticed 

 that sometimes chalk flints occurred, scattered in the 

 most wonderful manner through the chalk. The flints 

 were found lying, without any apparent order, in the 

 midst of the chalk. They might pick away the chalk and 

 suddenly come upon a little nodule, often very irregular. 

 Sometimes it was perfectly rounded, like a bullet, but 

 frequently it was a very irregular mass, lying quite iso- 

 lated in the chalk. But besides these scattered flints, 



and much more abundant than them, were bands of flints, 

 and all who had made a journey to Brighton or by any 

 of the lines that run out of London, if they had looked 

 out of the window, must have noticed how regularly 

 those bands run for considerable distances. The 

 layers or beds of chalk were marked out conspicu- 

 ously by those bands of flint. Now he wanted to 

 call their attention, in the first instance, to the fact that 

 there were three varieties of these bands of flint. He 

 might mention in passing that these bands of flint were 

 very irregularly distributed. On the average the flint 

 bands generally occurred some three or four feet apart, 

 but sometimes two bands were seen quite close together. 

 At other times a thickness of six, eight, and ten feet and 

 more of chalk existed without flints. Now, these bands 

 of flint were of two kinds. Most commonly they 

 consisted of nodules, very irregular masses, ex- 

 ceedingly fantastic in form and outline, but arranged 

 in tolerably continuous lines side by side. In the second 

 place there was, though much more rarely, another 

 kind of flint bands — what were known as tabular flints. 

 These tabular flint bands were more or less continual for 

 a very considerable distance. Very frequently when 

 those bands were broken they could be seen to be not 

 single bands, but double, consisting of two layers meet- 

 ing along an irregular line in the middle. There was 

 another fact to which he must call attention, and that 

 was that sometimes these tabular bands give off layers 

 or other tabular masses, more or less at right angles, and 

 sometimes running obliquely from them, and the position 

 in the chalk was that those tabular bands generally lay 

 along cracks which were known as the jointing of the 

 chalk, along which the rock split up with tolerable ease. 

 So there was a tolerably clear distinction between those 

 two kinds of flint bands, the nodular and the tabular. 



Those were the chief varieties of flint that 

 would be observed in the neighbourhood of London or 

 in any part of the south of England that they were 

 likely to visit. Either the flints were scattered 

 through the chalk, taking very irregular form, or else 

 they occurred as bands, the bands being sometimes 

 nodular and sometimes tabular in character. Now, if 

 they were to travel as far as Norfolk or the north of 

 Ireland they would find flints occurring in still another 

 manner. In addition to the bands and the scattered 

 flint bands being sometimes tabular and sometimes 

 nodular, more frequently nodular, they sometimes found 

 flints of gigantic dimensions and of very curious form. 

 A specimen exhibited was like a pot ; sometimes it was 

 closed at the bottom, and sometimes it was open 

 throughout, and if they were fortunate to see them in a 

 bed, as at Horstead, in Norfolk, they might find them 

 arranged in a very singular manner. These flints were 

 found to make vertical series. One flint seems 

 to fit in the top of another somewhat irregularly, and 

 another time they found a long series of these gigantic 

 flints arranged vertically. These had received a very 

 curious name, and the origin of the name was still 

 more curious. He believed the name originated in 

 this way : The celebrated geologist Dr. Buckland was 

 making a tour in the north of Ireland, and he had 

 as guide an Irishman who conducted him to places he 

 wished to visit, and on his way the doctor picked up a 

 great number of interesting things, and the Irishman, 

 with natural curiosity, asked the names. The doctor 

 gave some of those wonderful compounds of Greek and 

 Latin which at first sight seemed so uncouth, and what- 



