276 Reviews—Gunn’s Geology of Norfolk. 
stone’ (which has been classed with the Gault just before)! In this 
particular case there is no doubt about the lithological division, the 
white Chalk, the red ‘Hunstanton limestone,’ and the brown irensand 
of the Lower Greensand contrasting very strongly.* 
We are glad to see that Mr. Gunn treats of the Chalk in different 
divisions, which we should like to hear more about. This formation 
will almost everywhere bear more notice than has been given to it. 
As to its being ‘composed of a soft white mud, which has passed 
through the bodies of Worms and the intestines of Fishes,’ surely 
other classes of animals had something to do with the matter ! 
In speaking of the Lower Eocenes, Mr. Gunn is not quite clear, 
for he says that the London Clay ‘with the Woolwich and Reading 
Ser'es overlies the Chalk ;’ as if the first two were parts of one for- 
mation. The absence of the Thanet Sand might have been noted. 
The account of the Norwich Crag of course takes up some space, 
and a full list t of fossils (172 species) from that bed is given. It has 
been thought that the Red Crag and the Norwich Crag are the same; 
partly because they never occur together. Mr. Gunn thinks that 
‘they are one continuous formation, occupying a long period of time, 
during which the land has been gradually rising; and that in the 
process of upheaval, they may possibly bear to each other the same 
relation as the upper valley-gravels bear to the lower.’ The remark 
is .to the point, but the tenses are bewildering. ‘The overlying 
fluvio-marine ‘ Forest-bed,’ with its many remains of Elephant and 
Deer, next claims attention; and is succeeded by the ‘ Laminated 
Beds,’ a sort of ‘warp.’ 
The Glacial Drifts are divided into: (1) Lower Boulder-clay, or 
Till, ‘mostly (of) a greyish blue, but occasionally of a reddish tinge,’ 
and containing ice-scratched boulders of many kinds of rocks; (2) 
stratified Clays, with Sands and Gravel, which ‘lie upon the de- 
nuded surface of the Till, generally with a thin layer of beach- 
shingle intervening,’ and are often much contorted; (3) Upper 
Boulder-clay, with scratched boulders, chiefly Oolitic, flint, and 
Chalk. The Mundesley fluvio-lacustrine bed, filling an old valley 
cut through the Boulder-clay to the Forest-bed, is also here classed 
with the Glacial Series ; but strictly this is hardly right. The same 
may be said of the Valley-formations, in the account of which Mr. 
Gunn has availed himself of Mr. Prestwich’s late researches. It is 
to be noted that Norfolk is one of the ‘ flint-implement’ counties. 
The author concludes with an interesting account of the growth 
of peat, the incursions of the sea, and the formation of sand-dunes. 
In the hope that this useful little work may reach a second edition, 
we suggest, besides the few points already noticed, that a small 
geological map would be a great improvement; that the list of 
* A marked case of the result of trying to classify a set of beds by fossils alone 
occurs in a late number of the Journ. Geol. Soe. (vol. xx. p. 99), where, in a classi- 
fication of the English Tertiaries, the Upper and the Lower Bagshot Beds are 
missed out, we suppose because they do not yield fossils, and therefore, though 
sometimes 200 and 600 feet thick respectively, are not worth taking into account! 
t+ Prepared by Mr. 8. P, Woodward. 
