TIIH 1'I.KISTOCKNK SKIIIKS 627 



Above the Cromer t'rrsli water beds and be-low the Glacial deposits 

 there an- t\v< <li:-coiitiniioiis lieds which appear to be the oldest 

 l'I-i>torene 1'ifds in Norfolk. 



The Leda Myalls Bed is only found between Old Hythe and 

 dinner, for ,-onth of C'roiner it either thins out or is cut off by the 

 l>oiilder-t -lay. The bed consists of fine current-bedded loamy sand, 

 witli thin seams of loam and gravel. The fossils are marine, and 

 indicate a depth of 5 or 10 fathoms, as some of the bivalves occur 

 with the valves united in the position of life. All the Mollusca 

 yet found (nineteen species) belong to living species, and they 

 include two characteristic crag shells, Neptunea antiqua and Tellina 

 obliqua. One of the best exposures is at Runton Gap, near Cromer, 

 wlu-re Lrtla infltlia, M^ya arenaria, and Astarte boreali* may lie found 

 in position of life, and the bed is 15 feet thick. 



The Arctic Fresh-water Bed was first described in 1880 7 by 

 Mr. C. Reid, who then distinguished it from the Forest Bed, and 

 placed it in the Pleistocene Series, because the plants it contains 

 indicate a great change from the climate of the earlier bed. Trees 

 seem to have entirely disappeared, and the plants include the dwarf 

 Arctic birch (Betula nana\ the Arctic willow (Salix polaris), and 

 nurses which now only live within the Arctic circle. It consists 

 of a layer of clay and loam about 2 feet thick, but is not by any 

 means continuous, having only at present been found at three 

 localities on the coast, viz. Beeston, Mundesley, and Ostend, near 

 Hart on. At Mundesley it has yielded freshwater shells, elytra of 

 beetles, and bones of Spermophilus (a squirrel-like creature). 



The Cromer Till, where thickest near Happisburgh, consists 

 of two beds of tough grey unstratified boulder-clay, with an inter- 

 mediate band of finely laminated and ripple -marked clay. The 

 boulder-clays contain fragments of marine shells, with pebbles and 

 boulders of many kinds of rocks, including gneiss, mica-schist, 

 basalt, red and grey granites, " rhonibynporphyr " from Norway, 

 pieces of Carboniferous limestone, and pebbles of hard chalk 

 which have been bored by marine annelids, and subsequently 

 striated. 



The Contorted Drift is usually a yellowish marly and sandy 

 clay full of stones, so that it is really only a variety of boulder-clay, 

 but it exhibits a rude kind of stratification, and includes knots, 

 patches, and seams of sand and gravel, and the whole has a twisted, 

 contorted, and kneaded appearance. . Another remarkable feature 

 of the deposit is the occurrence of large tabular masses of chalk, 

 some of which are 20 to 30 feet thick, and from 100 to 180 yards 

 long. This drift contains boulders similar to those in the till 

 below and many broken shells, the latter being frequent in the 



