SOME ESSEX BOULDERS.
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clay which lie on the top of twelve feet or more of loamy gravel full
of great flints, quartzites, etc., these two boulders were sticking out
at a distance of sixty or seventy yards from one another. On examin-
ing them they were found to be Kimmeridge Clay, containing broken
pieces of Ammonites, but they were deeply grooved with parallel striae
on all faces, more especially the block at the western end of the cut-
ting. A friend took a photograph for me of the eastern end of the
cutting, shewing the block as it lay between the boulder clay and the
laminated clays; but since then the cutting has been widened and the
blocks have both been sacrificed to the needs of railway extension.
But besides these boulders, there are others of an entirely different
character, consisting of igneous rocks. Of these I found one large
boulder of an exceedingly hard porphyritic rock, smoothed and some-
what polished, but scarcely at all weathered, lying in a ditch in an out-
of-the-way lane in the parish of Great Waltham. And at Little Saling
there are two large blocks of dolerite, one lying near the churchyard
and the other at Mr. J. Smith's farm. The latter measures roughly
three feet by three feet by one foot four inches; it was dug out of a
ditch on the farm not long ago, and was transferred to the farm-yard ;
it is exceedingly hard and very close grained, yet it is smoothly
polished and very clearly striated on one side. The microscopic sec-
tions of these show that they are sub-ophitic dolerites, the one near
the church containing olivine in abundance, sharp and clear, with
not much augite, and the other containing no olivine, but augite in
abundance in granular aggregates.
It must always be a very interesting question as to where these
boulders came from. There can be no doubt that they were
brought by ice, in the glacial periods, whether land ice or icebergs,
and also very little doubt that they came from a northerly direction.
It is possible that the Carboniferous limestone may have come from
the Pennine range, and the Jurassic limestones from Yorkshire, and
that the porphyrites and dolerites are from Scotland, or perhaps more
probably from Scandinavia, but until some more definite evidence
can be obtained, it is impossible to speak with any certainty upon
such an exceedingly difficult question.
Essex Heronies.—In the fourth edition of Yarrell's "British Birds," edited
by Mr. Howard Saunders, F.L.S., is given the following list of Essex Heronies
(vol. iv. (1885), p. 165) :—Wanstead Park ; Sir John Tyrrell's, near Chelmsford ;
Chest Wood, Layer de la Haye (nearly 100 nests in 1877) ; and St. Osyth Priory.
We shall be glad to have any information about these heronies, or others un-
recorded, for publication in the Essex Naturalist.—Ed.