185 
to give to the geological map-maker the blessing of an easy, copious, 
elegant,eprecise, and universal language. 
To the Memoir are appended an Alphabetical Index to the Hills, 
and a list of the Hills arranged according to counties. 
A paper was afterwards read, “ On the Detrital Deposits of part 
of Norfolk, between Lynn and Wells;’ by Joshua Trimmer, Esq., 
F.G.S. 
The part of Norfolk described in this paper, is bounded by a line 
drawn from Lynn through Fakenham to Wells. The secondary strata 
consist of chalk and a band of green-sand and Kimmeridge clay on 
the borders of the Wash. The crag is considered to be wanting ; but 
above the chalk are two deposits, neither of which, in Mr. Trimmer’s 
opinion, is due to ordinary, long-continued marine action, but to pow- 
erful currents of water. The upper deposit consists of ferruginous 
sand or loam, containing numerous chalk flints, and a few fragments 
of red chalk, ferruginous sandstone, quartz rock, trap, porphyries and 
other formations. Mr. Trimmer does not pretend to identify any of 
these rocks with those of Scandinavia; but he says, if some of them 
have not been derived from that country, he knows of no other de- 
posit in that part of Norfolk in which Scandinavian detritus is to be 
found. He has not seen any fragments actually imbedded of suffi- 
cient size to merit the appellation of boulders, though such masses 
are often placed to protect the angles of houses and gateposts. The 
lower deposit is composed of the ruins of chalk mixed with variable 
proportions of argillaceous and arenaceous materials. In its purest 
form it resembles chalk, but in adjoining sections it is often lam- 
inated with irregular layers of sand or gravel, or so much mixed with 
them, as to assume the appearance of a gravelly, calcareous loam. 
Near Lynn it consists of fragments of chalk in blue clay. It is in 
general destitute of detritus foreign to the chalk, Mr. Trimmer 
having noticed in it only one small pebble of sandstone. Unabraded 
tabular masses of flint, from 12 to 24 inches broad, are dispersed 
irregularly through it. 
In neither of the two deposits has the author found any organic 
remains, except those derived from the chalk or the oolites. 
The depth of these accumulations varies so greatly, that within a 
few hundred yards the chalk may in one place be barely covered by 
a film of sand and gravel, and in another be overlaid by a bed 20 feet 
thick. The deepest and purest bed of chalk-rubble examined by Mr. 
Trimmer is at Gallows Hill, near Burnham Market, and consists in its 
upper portion of finely comminuted chalk, partially worn fragments 
of chalk, and tabular, unabraded flints; but the lower four feet con- 
tain irregular layers of sand, which in one part increase to a lenticu- 
lar bed of-rounded and angular flint gravel. 
The surface of the chalk-rubble is constantly indented with sand- 
galls, many of which Mr. Trimmer assigns to the action of currents 
of water; and he suggests that those which are cylindrical and a few 
inches in diameter, descending obliquely into the body of the rub- 
ble, may have been formed by eddies, whirling pebbles in their vortex. 
& 
