Geological Society. 553 
parative columns of those derived from some unpublished observa- 
tions of M. Arago, and of those of M. Anglada. 
GEOLOGICAL SOCIETY. 
_ (Continued from p. 160.) 
Dec: 16, 1835.—A paper, entitled “‘ Notes on the Geology of Den- 
mark,” by Dr. Beck of Copenhagen, and communicated by the Presi- 
dent, was first read. 
The only part of the Danish dominions in which gneiss and gra- 
nitic rocks like those of Scandinavia appear, is in the north-east of 
the Island of Bornholm. To the south and south-west of these for- 
mations in the same island, are beds considered to be of the age-of 
the Silurian system of Mr. Murchison; and on the eastern side of it 
are strata of the cretaceous period, all the intermediate groups being 
wanting. 
Respecting the exact age of the lower part of the cretaceous beds 
in Bornholm, much difference of opinion has existed, By some it 
has been referred to the old carboniferous formation, on account of 
the presence of large quantities of coal, and impressions of ferns; by 
others to a lignite deposit of a very new or diluvial period; by M. 
Alexander Brongniart to the age of the lias ; by Dr. Pingel to the 
iron sand of Messrs. Conybeare and Phillips ; and by Dr. Beck to the 
English strata, from the Hastings sand to the upper green sand in- 
clusive. The fossil ferns found in these beds belong to the genus 
Pecopteris, and some of the species have been named by M. Adolphe 
Brongniart. The seed-vessel of a monocotyledonous plant of com- 
mon occurrence in these strata, and considered by Dr. Beck to belong 
to the family Restiacee, is identical with one in Mr. Mantell’s collec- 
tion obtained at Heathfield in Sussex. ‘The few shells associated with 
the ferns which the author has examined are marine; and he conceives 
that these Bornholm beds were deposited in the sea at some distance 
from the mouth of the river which formed the Wealden system of 
England. 
To the south of these coal-bearing strata are beds of siliceous and 
calcareous sand, containing between 30 and 40 species of shells, which 
also occur in the upper green sand of England: and in the neigh- 
bourhood of Arnager is a small patch of greyish white chalk with very 
few flints, but abundance of fossils, agreeing with those of the lower 
white chalk without flints at Southerham near Lewes. 
In Denmark Proper the oldest formation belongs to beds of the 
cretaceous series, younger than those in the island of Bornholm. 
The lowest strata consist of pure white, soft chalk, with many layers 
of black, nodular flints, and contain more than 300 species of fossils. 
Among these remains, Ammonites are extremely scarce, Marsupites 
are unknown; and the remains of fishes, except teeth of the shark fa- 
mily, are very rare: but small zoophytes and microscopic foraminifera 
are very abundant; and, in some instances, animals of the sponge 
tribe, replaced by flint or chalcedony, but retaining their form, con- 
