140 PROF. PRESTWICH ON THE AGE, FORMATION, AND 



Sandstone, but from the pebble-beds of Lower-Eocene ("Woolwich) 

 age. 



The composition of this gravel renders it obvious that it is derived 

 from the Chalk and Tertiarieson the hills to the north of Limpsfield. 

 The escarpment is there capped by the lied Clay-with- flints, with iso- 

 lated outliers of Tertiary strata. One of the most important of the 

 latter, consisting chiefly of a mass of flint-pebbles, occurs at Worm's 

 Heath, three miles north of Limpsfield. It has there been much dis- 

 turbed, and the pebbles are mixed with numerous angular and 

 subangular flints. Elsewhere on the escarpment there are some 

 less disturbed pebble-beds. The escarpment at Titsey above Limps- 

 field rises to the height of 800 feet to 866 feet, but there are depres- 

 sions w^here the level is from 50 to 100 feet lower, while near 

 "Warlingham there is a gap which is still lower by 100 feet, and bare 

 of the Red Clay. It may have been through some of these that the 

 streams of Tertiary pebbles, and the flints from the Red Clay and 

 the Chalk, descended into the then flat and broad valley between 

 the Chalk and Lower-Green sand range ; while it is to be observed 

 that, although the Lower-Greensand range, ^ mile south of the 

 Limpsfield gravel-pits, is capped by beds of Chert and Eagstone, no 

 fragments of these have been met with in that gravel, although they 

 are common in the adjacent brick-earth pits. 



No organic remains of any description have been discovered in the 

 Limpsfield gravel *, though it has been worked for many j^ears. 

 Mr. A. Montgomery Bell has, however, found a large number of 

 Palaeolithic implements on the Common, and over the adjacent fields 

 of Broomsland Farm on the very summit of the watershed (see figs. 5 

 and 6). They are mostly of the pointed and ovoid types, similar on 

 the whole to the smaller Amiens implements, or to those 1 have named 

 "the hil] -group of Ightham"t. Erom their position, there was reason 

 to suspect their connexion with the underlying gravel ; but it was 

 possible, on the other hand, that thej^ might be associated with a 

 wider spread of the adjacent brick-earth, which belongs to a subse- 

 quent stage. It was long before that point could be established, 

 for though a few worked flakes had been discovered from time to 

 time in the gravel, it was not until last year that Mr. Bell obtained 

 a large, well-finished, pointed implement, grey and patinated, of 

 the ordinary St.-Acheul type. I will not enter further into the 

 discovery and spread of these implements, as they will, I hope, 

 shortly be described at length by Mr. Bell, to whose persevering 

 researches their discovery is due. 



As the Drift-gravels of the Darent Valley have been described 

 by Mr. Tople}^ I need only notice them so far as thej^ assist in con- 

 necting the Limpsfield bed with known horizons in the Thames 

 Valley, or with those drift-beds that have been brought to light by 

 sections made since the date of his memoir. He remarks of the 

 Limpsfield gravel that the most interesting point about it is that it 



* I first visited this and the adjacent pits in search of Mammalian remains 

 in 1849. 



t Quart. Joum. Greol. Soc. vol. xlv. (1889) p. 284, and pi. x. 



