THE ROMANO-BRITISH BARROW ON MERSEA ISLAND. 263
Mr. Reid remarked that the assemblage is that of plants which
grow habitually on wet meadow land. One noticeable feature
of the list is that it includes no cultivated plants. The abundant
remains of Fumitory and Wild Radish were rather suggestive
of former cultivation ; but, as both these plants have been found
fossil in British Pleistocene deposits, their evidence is inconclusive
on the point.
Further, I washed out samples, selected from various levels,
of the grey material which composed the core of the barrow.
These yielded seeds which appeared to me to represent the
commonest species in the above list ; but, as those seeds actually
identified gave so little information of interest, these others
have not been determined in detail.
The original surface beneath the barrow likewise yielded
a little moss, and the elytra of beetles. These have not been
determined ; but, together with a series of the seeds, they have
been placed in the keeping of the Essex Museum of Natural
History at Stratford.
(3.) GEOLOGICAL OBSERVATIONS.—I submitted five
samples of the material of which the barrow was built to Mr.
G. M. Davies, F.G.S., of the Imperial Institute, South Kensing-
ton, and I am indebted to him for the following report upon
them :—
(1.) Ironstone at 10ft. 6in. from top of mound.
Two pieces of coarse sand and earth cemented by hydrated oxide
of iron. A film of black or dark red limonite is generally visible near
the centre of the slab, and the degree of cementation diminishes above
and below this, giving a fairly-compact slab about 3/4 inch thick.
The less-ferruginous outer portions can be crumbled and washed
clear in water, the binding material being little more than ochreous clay.
A clean quartz-sand results, with a little flint in the form of pebbles and
splinters. Small pieces of black coaly matter are present, probably
charcoal. On heating, the ironstone produces an "organic" smell, and
results in reduction to magnetic oxide of iron.
The heavy minerals in the washed sand, apart from abundant spheroidal
concretions of impure limonite, are ilmenite, garnet, zircon, tourmaline,
rutile, staurolite, hornblende, epidote, kyanite, and andalusite.
(2.) Grey Material at 11 feet.
Grey loamy sand with flint pebbles. Two fragments of red chert
were also noted. Under the microscope these appear rather coarse in
texture, with cylindrical inclusions of iron oxide. Those appear to repre-
sent sponge spicules, one example in particular resembling part of a
tetractinelled spicule. Small fragments of charcoal and numerous rootlets