GEOLOGY 



Irregular hollows of the old estuary however remained and held great 

 sheets of water, some of them in the direct course of the rivers, others 

 isolated from them, and only connected by narrow artificial channels 

 called ' gatways.' These are the Broads which form such picturesque 

 features in East Norfolk. They vary in size from small pools or ' pulks ' 

 to sheets like that of Wroxham covering 92 acres, and Hickling 578 

 acres. All appear to be slowly filling up and contracting by the mud 

 brought down by the rivers, by peaty accumulations, and by the growth 

 of reeds and rushes along their borders. 



The tide now flows up the Waveney as far as Shipmeadow Lock 

 (27 miles), up the Yare to Norwich (29 miles), and up the Bure to 

 Wroxham (25 miles). Higher up the streams are navigable by means 

 of locks. The artificial hindrances to the flow of the streams have, in 

 times of long continued and heavy rain, Jed to disastrous floods, such as 

 that which occurred at Norwich and elsewhere in the county in 1878. 



Comparatively little erosion now appears to be taking place along 

 the river valleys. The rivers have reached their base-level, and the 

 tributary streams alone are able to deepen their courses. As Mr. Reid 

 has remarked the waste of the coast-line has undoubtedly curtailed the 

 drainage areas of some of the rivers, especially that of the Bure, and 

 consequently the waters have become more sluggish.^ 



The boundary between Norfolk and Suffolk is marked by the 

 courses of the Waveney and Little Ouse ; and it is a remarkable fact that 

 both rise near together at South Lopham, in a sandy tract intersected by 

 dykes. A 'causeway' about 86 feet above sea-level now forms the 

 division between the two drainage areas. 



If the rivers now appear to exercise but little influence on the waste 

 of the land, this is not the case with the sea. 



The waste of some portions of the Norfolk coast has attracted a 

 good deal of attention, but there are compensations in the growth of land 

 on the Fen margins, in the heaping up of blown sand which has been 

 banked up against the old cliff south of Winterton, and in the growth at 

 Yarmouth. 



The clifi^s elsewhere between Happisburgh and Weybourne waste 

 away at a rate estimated at from two to three yards a year, so that two 

 or three miles may have been lost since Roman times. Since the 

 Norman period, indeed, several villages, Shipden, Wimpwell, and great 

 part of Eccles-next-the-Sea, have been washed away. The waste is 

 accelerated by landslips which occur along the coast, the irregular 

 accumulation of contorted loam and clay with basin-shaped hollows of 

 sand and gravel being peculiarly susceptible to the influence of springs 

 which loosen and undermine the strata. 



Mud streams are also a noticeable feature along the coast ; while 

 the wind, as before-mentioned, lends its aid in the destruction. Then 

 the sea washes away the tumbled material and the coast is ready for 



* Reid, Geology of Cromer, p. 131 ; J. H. Blake, 'Geology of Yarmouth,' etc. (G«/. Survey), 



1890, pp. 62, 73. 



27 



