'60 Transactions of the 



descends to the foot of the Downs in both directions, by a long series 

 of undulations, while nearly all the streams which take their rise in 

 it flow right through the chalk escarpment as though they had had 

 channels dug for them. There is no doubt that the chalk formerly 

 covered the whole of this area, and that the sti'eams which then 

 flowed across it, either northwards or southwards, held on their course, 

 while in the course of ages the most elevated part of the chalk got 

 carried off, and the lower beds which are now seen were exposed to 

 view. 



These are the Wealden Beds, of which I am to speak to-night — 

 their history, too. is interesting. 



At the close of the oolitic period, before the waters of tlie deep 

 ocean, in which the chalk was deposited, covered our part of the 

 world, a large river, probably coming from the north-west, flowed 

 into the sea and lei't a delta, tlie remains of which we now see in 

 Dorsetshire, Kent, Sussex, and on the opposite coast of France. At 

 one time it brought down sand, at another mud. Plants grew thickly 

 on its banks, and by their decay formed peat, now converted into coal. 

 Gigantic lizards browsed on the vegetation, while crocodiles fed on 

 hard-scaled fish in its waters ; and its lagoons, alternately fresh or 

 salt according as the sea or river got the mastery, gave shelter to 

 multitudinous oysters or fi-esh-water mussels. Of all these changes 

 the rocks are witnesses. 



One of the main divisions of the "Wealden Beds is the Ashdown 

 Sand, a rock which is, however, not always sandy, but contains in 

 places thick beds of limestone. This is the only available stone for 

 building and for making roads in many places, and is therefore 

 valuable. To obtain it the upper soil and clay are removed, the 

 stone is quarried, the clay is put back again into its place, and a fresh 

 part laid bare. Field after field is in tlais way worked through, and 

 thoroughly turned over to a depth of from twelve to twenty feet. A 

 new pit had been opened last summer near Hastings, and on entering 

 it, I at once observed a band of hard stone a short way above the 

 limestone, but unlike it, composed of pebbles. Pebble-beds are very 

 uncommon in the Weald ; M^hen they occur they are found to consist 

 of quartz, and the pebbles are usually small: the largest I ever 

 found weighs just imder four ounces. They are usually very much 

 rounded, but in one case I found a crystal of which some of the faces 

 were clearly visible. On breaking a fragment of this pebble-bed, I 

 found it to be so firmly cemented that many of the quartz-pebbles 

 broke right through, and that beside these there were many pieces of 

 bone also, more or less rolled. On further examination I found 

 numerous bones, teeth, and scales, and the quarryman told me that 

 there was any quantity to be had. So I bought the whole bed of the 

 man, at the same price as that which they gi.t for the limestone below, 

 and wrote at once to Professor Sedgwick, who, with his unfailing 

 courtesy, sent, in a day or two, Mr. William Keeping, curator of the 

 Woodwardian iluseum, to help me to coUect. For several days we 



