102 Proceedings. 



formed in seas of greatly varying depth, known as the Cre- 

 taceous system. 



In considering the formations I have mentioned we will 

 start from the clays forming the floor of the great Weald 

 Valley in our district ; then going in a northerly direction we 

 will ascend the range of sand hills, of which Leith Hill, Park 

 Hill, Eedstone Hill, and Tilburstow Hill are prominent 

 members ; then coming over the valley in which we are now 

 situated, known as Holmesdale, also with its floor of clay, 

 we will lastly make another ascent up the steep escarpment 

 of the chalk, which forms the North Downs. 



In considering the clay of the Weald and how it came to 

 be where it is, we must look back a very long time to a 

 period when a great river, only comparable in size to the 

 largest rivers now existing in the tropical parts of our present 

 continents, flowed over the spot now beneath our feet, and 

 emptied its flood of waters by an immense delta into a sea 

 the site of which is now occupied by a large part of the 

 present Continent of Europe. 



Being a river, though a large one, we must not expect to 

 find the various sediments which were deposited by its waters 

 so widely spread as those formed at the bottom of an exten- 

 sive sea ; but we know that the surface covered by them was 

 considerable, for we find them extending over a space 200 

 miles wide from N.W. to S.E., and 320 miles in a direction 

 from W. to E. This area, it has been remarked, does not 

 exceed that occupied by the deltas of some of our existing 

 rivers, as that of the Afiican Niger, which extends 170 miles 

 inland, and occupies a stretch of 300 miles with its many 

 mouths. 



In examining the deposits of the Wealden river we obtain 

 evidence not only of the position of the continent which it 

 drained, but at the same time of the character of some of the 

 rocks which composed that continent, for if we go over to the 

 western part of the delta, in France, we find fragments of 

 oolitic rocks which we know from their character to have 

 been derived from the north-west of England. At Cuckfield, 

 in Sussex, we find, too, pebbles of Quartz and Jasper, and we 



