288 Mr. R. C. Taylor 07i the Geology of East NoffolL 



which man has fixed his abode and covered with his species. 

 This crag rests in part upon the London clay, and a lami- 

 nated clay withoxit fossils, perhaps the plastic clay, and partly 

 upon the chalk, occupying the lowest sites ; rarely rising to 

 80 feet above the present level of the sea, and in general not 

 more than half that elevation. The average level of its base 

 may be considered to be about that of the present ocean. In 

 certain cases, where the chalk hills attain a higher level than 

 the crag, that deposit could only be expected to envelop or 

 surround their sides, and not to penetrate i7ito the chalk. Such 

 eminences would then present the appeai'ance of tongues or 

 promontories of chalk, protruding into the crag; and this cir- 

 cumstance accounts for the occasionally apparent absence of 

 that formation. 



But the crag itself has, at the last of the geological epochs, 

 been subjected to abrasion by the diluvial currents to which 

 allusion has been made. Portions, probably from its western 

 edges, have been swept away. Their fragments, mingled with 

 those of the chalk and preceding formations, piled in enormous 

 heaps, form the cliffs of Cromer and Trimingham 250 or 300 

 feet in thickness, upon the original crag, which rests, m situ, 

 at their base. The proof of the disruption and transportation 

 of more ancient strata, may be observed in the enormous de- 

 tached masses of chalk, in these diluvial cliffs, at various ele- 

 vations above the crag. Near the light-house hill at Cromer, 

 one of these insulated patches is 150 feet high, and has a 

 kiln upon it, in which lime of an excellent quality is burned. 

 Further on, at Runton, is a large mass 80 feet thick : another 

 rises to the height of 100 feet; and at Sherringham is another 

 still higher. In all these cases, they rest upo7i the crag, proving 

 alike the breaking up of the older strata and the continuity of 

 the later. (See the Section No. IV.) 



We have yet to consider one remarkable accompaniment 

 of the upper marine formation, upon the Norfolk coast. This 

 consists in that alpparently continuous bed of vegetable sub- 

 stances, with which the crag is frequently in contact, at an 

 irregular elevation ; sometimes above and sometimes below the 

 high-water line. This coincidence had been remarked in 1822 

 along about 25 miles of the coast ; but it was more obvious 

 after the unusually high tides, in February 1825, had carried 

 away large portions of the cliffs, leaving the woody stratum 

 exposed. At some points this bed consists of forest peat, con- 

 taining fir cones and fragments of bones ; in others, of woody 

 clay; and elsewhere of large stools of trees, standing thickly 

 together, the stems appearing to have been broken off about 

 18 inches from their base. They are evidently rooted in the 



clay 



I 



