86 



parts marked U.P. The appearance has been well named 

 "festooned." {Fig. i., ii., iii., v., ix., &c., PL i.) In a 

 section taken at right angles to this the resemblance to 

 festooning gives place to what is commonly called 

 "contorted" {Fig. iv., vi., viii., &c., PL i.) because the 

 regularity is not so apparent, though of course they are 

 interchangeable terms, and sections at angles less than 

 right diminish the distinction. 



As exhibited in the latest fit of glaciation, the direc- 

 tion of these folds is always across the inclination of the 

 surface of the ground at present. The length of these 

 folds is various, and direction sinuous. At Erith I have 

 been able to trace a wave or ridge over 50 yards in length, 

 where the surface was being cleared to get at the Brick- 

 earth, its line was irregular but continuous. 



In Greenstreet Green, Darenth, gravel pit, lengthened 

 longitudinal ridges of gravel, parallel with the valley, 

 may be traced in the bottom of the pit, which could only 

 have been formed by the descent of masses from the hill 

 side, so also at Pratt's bottom, &c. 



Usually, however, the length, either originally or from 

 subsequent interference, is very much shorter and in curves 

 of small diameter, which when cut through in a right line 

 parallel to its general extent, give the appearance of 

 gullies running in the opposite direction. 



It is a distinctive feature of these earth folds that they 

 all extend at right angles to the direction of the surface 

 drainage. Where either in or through the latest layer of 

 trail and across the folds of underplight, marked channels 

 are found to have been excavated, in accordance with the 

 present inclination of the surface and the direction of its 

 drainage, they are of later date and indicate the gradual 

 resumption of the reign of rain as we have it 

 now. 



The "hammer headed " masses of chalk or underlying 

 rock are the result of the passage of a later mass of ice 

 over llip fold, flattening it out; the "hammer heads" are 



