﻿Clement Reid — Pliocene Beds near Cromer. . 303 



20ft. from what it is at present, which (if we consider the fall of the 

 tides to be unaltered) would bring the colonies of Mija arenaria, 

 Mytilus ecluUs, and Tellina obliqua to a few feet below low-water, 

 while Pliolas crispata would occur between . tide marks. Although 

 Tellina obliqua and T. BaWiica occur with the valves united at 

 Weybourn at a higher level, yet here they are not in their natural 

 position, and the beds appear to have formed a sandy and muddy 

 beach such as is often seen at the mouths of rivers. 



Fresh-wateb Bed. 



Above, and often resting on a slightly eroded surface of the marine 

 and estuarine beds already described, are shown extensive deposits 

 of freshwater sand, clay, and peat. These beds are much more ex- 

 tensive than is commonly considered, and appear to have been formed 

 in shallow lakes like the present " broads " of Norfolk. They can 

 be traced with but short interruptions from Weybourn to West 

 Eunton, and again from Overstrand to Mundesley.^ 



In places rootlets penetrate three or four feet into the Weybourn 

 Beds, marking the position of islets in the lakes, or perhaps be- 

 longing to water-plants, in which case they would indicate where 

 the fresh- water deposits have been denuded. This "rootlet bed" 

 may be traced at intervals between Happisburgh and Weybourn 

 Signal Station, but the rootlets do not always penetrate beds on the 

 same horizon.^ It is noticeable that none of these roots belong to 

 anything larger than brushwood, as observed by Mr. Gunn in a 

 similar bed at Kessingland. 



The Fresh-water Bed appears to have been formed when the re- 

 lations of sea and land were much as they are at present, for although 

 in several places between Sherringham and Mundesley it has filled 

 hollows a foot or two below high-water mark, the channels seem 

 never to be cut deeper, apparently showing that they had reached 

 the sea-level. 



The mammals from this bed have been carefully collected at 

 West Eunton by Mr. A. C. Savin, and the list already contains two 

 or three species not known in the Forest-bed. It has also yielded 

 the wing-bone of a bird, seeds, beetles and numerous mollusca. 

 JProm this locality I have obtained the following species of land and 

 fi-esh-water shells : — 



Paludina contecta. 

 vivipara. 



Valvata piscinalis. 



crista ta. 



JBi/thinia tentaculata. 

 Planorbis albus. 



■ complanatus. 



contortus. 



corneus. 



• nautileus. 



spirorbis. 



Limncea palustris. 



peregra. 



stagnalis. 



truncatula. 



Ancylus lacustris. 

 Limax, 2 sp. 

 Succinea putris. 

 Helix arbustorum. 



hispiida. 



nemoralis. 



Zua lubriea. 



^ It should be remembered that there are two fresh-water beds at Mundesley, one 

 older than the Lower Boulder-clay, the other newer, and probably Post-glacial. 



- Near Weybourn, where the Fresh- water Bed rests dh-ectly upon the Chalk, the 

 joints and crevices in this rock are often filled with peat. 



