132 



PEOF. PRESTWICH ON THE AGE, PORMATION, AND 



also to the escarpment, is given in PI. YI., figs. 1 and 3, the former 

 showing the gradient of the plateau from Morant's Court Hill to the 

 Cray Valley, and the latter the relation of the hill to the adjacent 

 part of the escarpment. These make it evident that the older drift 

 is clearly independent of both the valley-systems, and that the drift 

 on this Chalk plateau, like that on the Ash plateau, is of greater 

 antiquity and distinct from that of the valley of the Cray and its 

 tributaries. 



The following lists, brought up to date, of the approximate num- 

 ber of specimens of the Chalk-Plateau or Ash type, found at the 

 several localities above mentioned, will show how important this 

 plateau-group has become. Por those on the west plateau, with 

 the exception of Morant's Court Hill and Currie Parm, I am in- 

 debted to Mr. De B. Crawshay, and for those on the east plateau 

 to Mr. E. Harrison. Mr. Crawshay has likewise a considerable 

 number of specimens from Ash, West Yoke, and Bower Lane. 



Chalk Plateau, West. (See Map, Plate YII.) 



Height above j -^^^ 



sea-level ^ , Flakes. 



• n , ments. 



m leet. 



1. Stonehouse and Broke Farm, Halstead * ... 480 5 2 



2. Shacklands Wood, field west of 535 2 



3. Hewit's Farm, Chelsfield 470 1 



4. Northstead, bill west of 485 3 1' 



5. Betsom Hill, near Westerham 790 15 



6. Titsey Hill, near Limpsfield 864 3 



7. Ivy Cottage, Tatsfield 780 8" 



8. Currie Farm, Halstead 590 2 



9. * Morant's Court Hill, S. of Halstead 700 12 



Single specimens have also been found farther north at Park Gate, 

 Lullingstone, and at Cockerhurst, both above the 400-feet level. 



Chalk Plateau, East, 



Height above j^^^^er of 

 sea- level t i 4. + 



. r . implements t. 



1. Ash 490 ' 80 N 



2. South Ash 520 60 



3. West- Yoke Farm (1 mile N.W. of Ash) ...460 40 



4. Kingsdown 550 4 



5. Peckham -Wood Corner 637 2 



6. Plaxdale Green 630 2 



7. Bower lane (inclusive of Mr. Crawshay's 



specimens) , 520 30 



But these ancient implements are not confined to the central area 

 alone of the broad plateau. They extend, as on the west plateau, 

 to the very crest of the escarpment, up to its highest summit-levels 

 of between 700 and 800 feet (see PI. YI., fig. 3). Mr. B. Harrison 

 has found them at : — 



* I also have found a few specimens at these places, 



t A large number were moreover thrown away as duplicates, or as not worth 

 keeping. 



