536 
THE GEOLOGIST. 
pressed in the direction of the cleavage of the containing rock. The contortion 
is too great to admit of a determination of the species. 
Mineral Veins. — "Dear Sir, — Perhaps your correspondent 'J. C. ' will be 
so good as to particularize the examples on which he has come to the conclusion 
' that mineral veins, in general, contain more iron in limestone than in siliceous 
strata.' Many will, I think, be slow to admit this as an axiom, without good 
proof being furnished, and will recal to mind, as I do, numerous instances of veins 
ingranite and siliceous schists abounding in iron, in the common conditions of gos- 
san (earthy oxide), or of uiundic (pyrites), and where the productiveness of valuable 
ores seems to be materially influenced by its presence. In addition, the great 
mass of copper-ore (copper-pyrites) fi'om our chief British mining-districts is a 
' doulile sulphide of iron and copper,' so tliat the quantity of the former metal in 
very many veins is more than meets the eye. The question opened by your 
correspondent is a very interesting one, and I hope he will himself contribute to 
its elucidation by giving the facts, from both the limestone and siliceous rocks, on 
which he forms his opinion. — Yours truly, Henrt Thomas — Kennington Park." 
Mammalian Remains at St. Addresse. — " Four years since, when I inspected 
the collection of M. Plambard, at Ingouville (Havre de Grace), I observed in it a 
fragment of the grinder of an elephant, with very broad plates. The specimen 
was found on the neighboiiring shore at St. Addresse ; it must undoubtedly have 
come from the loam- or gravel-capping of the cliff's there, and as I was told no 
other similar remains had been previously found in that district, I have thought 
it worth while to send you a note of this fragment in connection with Mr. Prest- 
wich's inquiry. — M." 
'Pleistocene Fossils from Bedford. — "Dear Sir, — I have had some fossils 
sent me from the neighbourhood of Bedford from Odell. Can you tell me what 
formation the surface-clay in that district is lilcely to be ? I think the shells are 
Cyclas ohovata, and either Cyrena trigonula or Astarte. — Yours very faithfully, 
J. B. Canterbury." — The indication of the fossils named is, that the clay enveloping 
them is of Pleistocene (the latest tertiary) age. Bedford itself is on the Oolitic 
formation, which, like other secondary deposits, is there, as very commonly in 
other districts, covered over by the pleistocene gravels and brick- earths. Search 
should be made for other shells than those named, and, even more particularly, for 
elephant and other mammalian bones in this deposit ; such remains being of 
great value at this moment in the decision of certain very important geological 
questions. 
CitocoisiTE — Amber — Variation of Gulf Stream. — "Sir, — Wi 11 you 
tell me what the enclosed is ; a piece weighing about four pounds was picked up 
in a field in Carmarthenshire. The outside ])resented a dull yellow, worn 
appearance, as seen on one side of the specimen^ but its great weight induced us 
to break it; when the interior looked like a piece of lead ore coloured with oxide 
of iron. Would you also kindly insert in the Geologist the following queries. 1st. 
Amber is supposed to be derived fi'om the resins of extinct coniferaj In the 
Bath Museum there is a piece of amber containing a fish. How did the fish get 
into the gum of a tree ? 2nd. It was stated some time ago, that, owing to 
changes in the Gulf stream, we might expect a succession of warm summers. Is 
there any oscillation in the current ? If the change is occasioned by the partial 
filling up of the old bed, how can the change be limited ? Will it not go on until 
the warm current is thrown directly on the British Isles, and then altogether 
beyond our latitude ? — Ctmro." — The specimen received is Crocoisite, a chromate 
of lead, known also as red-lead spar. It is used for a pigment, but the colour is not 
permanent. The mineralogical tests will be found in " Nicol's Manual of 
Mineralogy," page 387, and in other treatises on that science. 
TiiiLOiiiTES Found in TnK Excavation of tiik Oxford and Worcester 
Railway. — We beg to acknowledge a communication from J. Gray. Estj., F.G.S., 
of llagley, inclosing gutta-percha casts of fragments of Acidaspis found in the 
cutting of the Oxford and Worcester Railway. 
Pennant Sandstone. — Whence the term Pennant, as applied at Bristol to the 
sandstone series between the upper and the lower coal-measui'cs ? — Cba£L£S 
Maexel. 
