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332 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. .May 19,
2. Middle Eocene Strata of Brussels.
.1.. Laeken beds. Dileghem, Jette, Laeken, ^'c.
I shall now pass to the neighbourhood of Brussels, the most im-
portant of the districts after Cassel, where I had an opportunity of
studjdng the Middle Eocene strata. The capital of Belgium is distant
from Cassel about seventy-five English miles, in a straight line due
east. In exploring its environs I had the great advantage of being
accompanied by my friend Captain Le Hon, who had made a fine
collection of tertiary fossils, and whose accurate knowledge of palse-
ontology enabled him to render me the greatest assistance. We visited
together most of the localities which I shall have to mention. M.
Deby also of Brussels accompanied us in many of our excursions, and
gave us much information respecting the geological structure of the
country.
The general level above the sea of the higher grounds or table-lands
round Brussels is about 300 feet, the valleys which intersect them
cutting to the depth of 200 feet and upwards, so as to descend to
within 60 and 70 feet of the sea-level. On the highest grounds, and
at many intervening elevations, loess is found (see Section, fig. 6).
Fig. 6. — Section near Dileghem, two miles N.N.W. of Bi^ussels.
A. Loess. y. Yellow and green sands.
B 2. Diest sands. E . . Laeken beds.
X. Bed of rolled flint-pebbles.
Thus, near Dileghem, two miles N.N.W. of Brussels (Map, fig. 3,
PI. XVIT.), it may be seen crowning the elevated platform (fig. 6, A).
Next in order iron-sandstone and green sands, exactly resembling
those of Diest (B. 2. fig. 6), about 10 feet thick, below which is a
bed of well-rolled flint-pebbles .x, fig. 6). Under this, yellow ferru-
ginous sands .y, fig. 6), with hydrate of iron and green sands, 30 feet
thick, and without shells, succeed. I had no means of determining
their age, whether they are contemporaneous with the beds of Mont
Noir near Cassel, before described as containing Middle Eocene fossils,
or whether they are part of the Limburg series, as I was assured by
several Belgian geologists.
At a somewhat lower level, sands, containing unquestionable Eocene
fossils, are seen in the fields at the points marked A. and B. in Map,
fig. 3, PI. XVII., but their contact with the incumbent beds, y, fig. 6,
is not exposed. Scattered over these fields, which are often called
indifferently " Jette" and " Laeken'* by collectors of fossils, and also
in a sand-pit from which shelly matter had been extracted for agri-