162 NORFOLK DRIFT. [Ch. XII. 



stated that upon the nuvio-marine formation repose laminated clays 

 without fossils, and these are followed by great masses of till or un- 

 stratified clay from 20 to 80 feet thick. Among the included frag- 

 ments of rock are some of granite, the largest of which are from 6 to 

 8 feet in diameter; also syenite, of Scandinavian origin, and the 

 wreck of the Norwich Crag, London Clay, chalk, oolite, and lias, 

 with boulders of more ancient fossiliferous rocks. 



The cliff-sections above described show that in various parts of 

 Norfolk and Suffolk several of the extinct as well as the living species 

 of mammalia lived after the accumulation of the glacial till and. 

 boulders, as well as before it. The Elephas primigmius affords an 

 example of one of these extinct species, and in many British locali- 

 ties the Elephas antiquus and Hippopotamus major occur in the allu- 

 vium of valleys of later date than the marine boulder clay. Some of 

 the valleys in question have been excavated through the glacial drift 

 after the latter had been upraised from the bed of the sea. 



At Mundesley, in the Norfolk cliffs, and at Hoxne, not only has 

 such denudation taken place, but the hollows near Diss, in Suffolk, 

 scooped out of the drift, have been again filled up with freshwater 

 strata, in some of which the remains of the elephant have been dis- 

 covered.* 



One of the formations of the Norfolk cliffs, above mentioned as 

 overlying the till, has been called contorted drift, so frequently are its 

 beds of gravel, sand, and clay, bent and folded back upon themselves, 

 in the same manner as parts of the Scotch drift, represented in fig. 

 137, p. 156. In some cases these contortions extend for a height of 

 70 or 80 feet, and they are coiled round isolated masses of chalk, 

 such as may have fallen in landslips from a perpendicular cliff on the 

 surface of a frozen sea, or of an ice-island first driven by the winds 

 and currents against a steep coast, and then carried away again by a 

 change of the wind until it grounded in a sea of sufficient depth to 

 allow of the deposition of its earthy and stony burthen on the spot 

 where it melted on the bottom of the sea. The bent and disturbed 

 beds often rest on strata of sand and clay, which are perfectly hori- 

 zontal; In those places where the contortions are on the greatest 

 scale, as at Sherringham for example, the chalk with flints at the base 

 of the cliffs retains its horizontality, and has evidently not participated 

 in the slightest degree in the violent movements to which the strati- 

 fied drift and the huge masses of chalk, transported bodily from their 

 original position, bear testimony. The probable causes of such par- 

 tial derangement in the strata so peculiarly characteristic of the gla- 

 cial period have already been spoken of (p. 157). The successive 

 deposits seen in direct superposition on the Norfolk coast imply at 

 first the prevalence over a wide area of the Newer Pliocene sea. 



* For a fuller account of these Norfolk deposits, see Lyell, Antiquity of Man, 

 chap. xii. 



