Mr. R. C. Taylor on the Geology of East Noffolk. 281 



at some distant period. In summing up, Mr. Robberds con- 

 ceives that the sea once filled the interior valleys to the height 

 of 40 feet, as marked by the ancient shells ; — that the tides 

 flowed at an elevation of 10 or 12 feet, at Burgh Castle, du- 

 ring the Roman occupation of that fort: — that at the Norman 

 Conquest they were only about six feet high : — that there have 

 been in every succeeding century, fewer and less extensive in- 

 imdations of fresh-water in these valleys : — that old navigators 

 observe within their remembrance, a sensible lowering of the 

 waters in the present channels; — and that all these circum- 

 stances combine to mark " a progressive depression in the 

 level of the adjacent sea." — " The rate at which this change 

 has proceeded, might probably be calculated with mathema- 

 tical precision ; the data are rather uncertain, but they seem 

 to indicate that the level of the sea has been regularly falling 

 about eight or nine inches in every hundred years, which would 

 carry back the period of its greatest elevation to about six 

 thousand years ago." 



Such are the inferences which the observation of Mr. Rob- 

 berds has enabled him to form. He proposes hereafter to 

 take a wider survey ; to show that throughout this quarter of 

 the globe, there are similar traces of the retiring waves, and 

 that there is evidence of a corresponding elevation of the In- 

 dian and Pacific oceans. 



In an inquiry of this nature, previously to assenting entirely 

 to certain conclusions, it will be permitted me to scrutinize the 

 *' evidence of change," so near home ; to examine the data 

 which have led to this conviction, and formed the ground- 

 work of the author's present arguments, and as may be con- 

 cluded of his future reasoning. 



Admitting at once the accuracy of the historical portion of 

 this evidence, it still appears possible to demonstrate, that all 

 the recorded and authenticated changes in the valleys under 

 investigation, since the epoch of the deluge, were effected 

 without any depression of the neighbouring ocean. 



A slight preliminary sketch of this district may be useful. 

 It includes ten principal valleys; all nearly upon the same 

 level, approaching to one plane surface, having the outfall of 

 their collected streams at Yarmouth ; there passing with diffi- 

 culty over the bar that obstructs the haven's mouth. Several 

 minor ramifications, with numerous bays and indentations, 

 almost incircle certain higher lands, forming greater or smaller 

 promontories. Other spots of elevated ground, provincially 

 termed Holms, rise, like islands, from the bosom of these 

 marshy flats. The whole character of the scene is that of an 

 arm of the sea, whence its waters have been withdrawn, or 



NewSei-ies. Vol. 1. No. 4-. Anvil 1827. 2 O whose 



