Mr. Rose’s Sketch of the Geology of West Norfolk. 29 
words, by the mighty debacle, and what was deposited by the 
usual currents found in large basins of water, into which huge 
rivers emptied themselves, that, with our present knowledge, 
in My opinion, we cannot apportion the effects due to each 
agent. ‘That the clays, particularly, are composed of trans- 
ported materials there cannot be a question, for the chalk 
which forms the substratum of the greater part of western 
and central Norfolk could not furnish the blue clay so fre- 
quently met with upon it: not only this, the boulders, so 
abundantly found in the clay, inclose organic remains 
which enable us to determine that their parent rocks are si- 
tuated fifty, nay hundreds of miles apart from them. With- 
out noticing the fragments of primitive rocks (which are more 
difficult to identify, in consequence of their not containing 
organic remains), I may particularize boulders from the old 
red sandstone, mountain limestone, alum-shale of Whitby, blue 
lias, cornbrash limestone, Septaria of the Oxford and Kimme- 
ridge clays, &c., all inclosing animal exuvize that indubitably 
determine from what strata they were disrupted. As many of 
these boulders weigh some hundreds of pounds, indeed, some 
tons*, it is fair to infer that no common current or torrent 
could have impelled them to their present sites, making every 
allowance for time; indeed, the magnitude of some of them, 
the distance they must have travelled, and the want of order 
in the arrangement of the clay, sand, and gravel, all combine 
to render it highly probable that the transport of these ma- 
terials could not have been effected by any other agent than 
the Noachian Deluge. 
The light lands covering the outcrop of the chalk abound 
in bleached fragments of flint, the debris of the abraded chalk; 
these fragments are in many places (as around Castleacre) so 
abundant, that it is found necessary to pick them from the 
and about once in four years, to the amount sometimes of 
two loads (24 bushels to the load) per acre. The clay of the 
heavy \ands is either yellow or blue: the former contains a 
large proportion of calcareous matter, and in it large fractured 
flints predominate, with their angles sharp; the blue clay is in 
a much greater degree argillaceous, and is also remarkable 
for the abundance of boulders of the oolitic series of rocks, 
having all their angles rounded. The gravel beds are prin- 
cipally composed of fragments (in the form of pebbles) of al- 
most every member of the series of rocks, from granite up- 
wards, with every angle effaced, manifestly the result of long 
exposure to attrition, ; 
In some situations, as is exemplified on Necton Common 
* A boulder of breccia in a clay-pit at Fouldon, south of Swaffham, 
weighs several tons. 
