472 
Geology of Norfolk. 
like that of the Nar, receiving in its upper part the drainage 
of the high grounds on the east. The warp also was not depo- 
sited until after the cessation of those agencies, whatever they 
were, which were so unfavourable to animal life as to have caused 
the absence of regular deposits of shells through a series of marine 
strata more than 300 feet thick. 
About a quarter of a mile higher up the vallev, a gravel pit has 
been opened in a superficial deposit of angular flints which appears 
to be of the date of the warp. 
The elevation of the Gaytonthorpe valley is probably somewhat 
greater than that of the valley of the Nar ; but the obscurity still 
hanging over these interesting deposits will not be wholly removed 
till a section shall have been obtained exhibiting the base on 
which the Nar clay rests, and till the heights of these valleys 
above the sea shall have been accurately determined. 
The elevation above the sea of the difTerent points in Sections 
I. and II. is in a great measure conjectural (see Note, p. 465), 
and the proportion between the vertical and horizontal scales 
greatly exaggerated, in order to render the different deposits dis- 
tinct. Were those sections constructed on a true scale, the ver- 
tical scale in Section I., which is the most exaggerated, should 
not have been greater than at present, on a base line 26 feet long. 
Agricultural Districts. 
The agricultural districts dependent on varieties of soil into 
which I divide Norfolk are the following: — 
T. The alluvial district of East Norfolk. 
II. The district of the deep upper drift. 
III. The district of the lower drift. 
IV. The district of the thin upper drift. 
V. The alluvial district of West Norfolk. 
Each of these consists of minor divisions. In describing the 
boundaries of the districts and sub-districts I shall refer to Smith's 
County Geological Map. 
I. Alluvial District of East Norfolk. 
This comprehends three sub-divisions: those of — I. Alluvial 
Sand; 2. Alluvial Clay; 3. Peat. 
The alluvial sand consists of the Yarmouth Denes and the 
hills of blown sand which stretch along the coast from Eccles to 
Hemsby, with an average breadth of less than a quarter of a 
mile. Though of little agricultural value, either from the extent 
or quality of their surface, they are indirectly of great importance, 
as on the maintenance of them in their integrity depends the 
exclusion of the sea from the valuable portions of the alluvial 
district of East Norfolk. 
