THE ZOOLOGY OF NORFOLK 49 
The rivers and broads of Norfolk are pre-eminently rich in Freshwater 
Polyzoa, as is well known through the intensive study the group has 
received from Mr. H. E. Hurrell, F.R.M.S. Plumatella fungosa occurs 
in large masses among the submerged roots of alders and willows at South 
Walsham Broad. Cristatella mucedo and Lophopus crystallinus are some- 
times abundant upon Elodea canadensis and water lily leaves at Brundall, 
particularly in the dyke leading into Surlingham Broad ; Fredericella 
sultana forms tangled masses upon submerged reed stems ; Plumatella 
repens and Paludicella Ehrenbergii also occur in the Broads. 
Chetognatha—The arrow-worms (Sagitta spp.) are sometimes plentiful 
in plankton. 
Echinodermata.—Asterias rubens is very plentiful off the coast and large 
numbers are often washed ashore after winter storms ; with them occur 
the sunstar (Solaster papposa) and Ophiura churned up from the sand. 
Here and there inshore shoals produce numbers of heart urchin (Echino- 
cardium cordatum), and the purple-tipped urchin (Echinus miliaris) is 
frequent among the seaweed-covered stones off the coast. 
Tunicata are poorly represented, and apart from Botryllus spp. on flint 
boulders they have been scarcely noticed. 
The information given in these notes on the fauna of Norfolk is neces- 
sarily incomplete, and it may be mentioned that the extensive collections 
made by the various workers in the different groups are housed in the 
Castle Museum, and members of the British Association are cordially in- 
vited to consult the members of the staff with regard tothem. One special 
feature of the Museum is the new Norfolk Room, where fine panoramic 
displays are to be seen illustrating the main physical units of the county. 
In the gallery above it is intended to make as complete a collection as 
possible of not only the fauna but the flora of the county, and the services 
ot local specialists have been secured to co-operate in making this material 
available as befits a county unique in its faunistic and floristic advantages. 
Ve 
GEOLOGY OF THE NORWICH 
DISTRICT 
BY 
Pror. P. G. H. BOSWELL, O.B.E., D.Sc., F.R.S. 
I. PHYSIOGRAPHY. 
As indicated in the chapter on Norwich in its Regional Setting, Norwich 
lies near the centre of an area of plateau country which is trenched by the 
valleys of the Upper Bure, Wensum, Yare and Tas. Of a general level 
D 
