21G 
THE GEOLOGIST. 
faithfully, J. R. C." — " Siii, — I have collected fossils for the last two years, more 
especially those from the chalk, but I tind it extremely difficult to prevent teeth, 
&c. from breaking off. I have used thick gum-water for sticking the specimens 
together, but I tind it very misatisfactoiy, in consequence of gum being acted upon 
by tiie weather. 1st. Can you reconmiend me any good cement of which chalk 
will not absorb all the moisture, and which will not show a black mark where the 
specimens are jdined I 2nd. Have geologists ever found any fossil pearls among 
the oyster ami otiier beds of fossil shells? — Yours, &c. Enquikee." — 1st. AU 
chalk specimens should be saturated in a weak solution of gum, size, or other 
similar material, before the joining (jf the fragments is attempted. Ackerman's 
cement, procurable at those well-known artist's colourinen's establishment in the 
Strand, is a very useful preparation for repairing chalk and other fossils. 2nd. 
Fossil pearls have been, although rarely, found. Sj)eeimens from the large Inoce- 
rand of the chalk have l)een long known. One very large and beautiful specimen 
is in the collection of N. T. Wetherell, Esq. of Highgate, and has been described 
in the " Annals of Natural History." 
Okiginaij Thickness op the Purbeck Dirt-bed. — " Sir, — In the volume of 
The Geoi^ooist for 18.58, is an article on ' Voices from the Rocks,' (p. 543). 
It is admitted by the author of that book, that the dirt-bed in the Isle of Portland, 
from whence so many fossil trees have from time to time been extracted, is from 
12 to 18 inches in thickness. 
" I had the pleasure of visiting that interesting dirt-bed a few years ago, and it 
strack me at the time that the bed of mould was originally very much thicker 
when it formed part of the surfiice, and when the trees were growing upon it, and 
before the bed of hard and compact limestone, 9 feet 7 inches thick, was depo- 
sited over it. 
" The enormous pressure of such a mass of stone upon such a bed of vegetable 
soil as the diit-bed then was, must have gi-eatly reduced its thickness. 
" We ought also to consider the effect which long periods of time would have 
on such soil, from the escape of the various gases which compose the humus 
always present in larger or smaller quantity in all soils. 
" With regard to trees thriving on a thin soil, I beg to observe that about seven 
or eight years ago, at a slate-quarry at Swithland, near Leicester, I saw a thrifty 
young oak having a tmnk 2 feet in diameter, gi'owing upon a large accunudation 
of fragments of slate, the refuse of the quarry, and thriving apparently without 
any soil except that formed of the fragments of slate. 
" This oak I thought was also a good memorial of the ancient date of the former 
working of the slate-quarry. — John Brown, F.G.S., Stanway." 
Shoal of Fish buried in Sand. — The following extract is from a paper 
entitled " A Week in Gaspe," by Dr. Dawson, in the Canadian Naturalist, for 
October last : — 
"On the long sand-point that, stretcliing for into the bay, shelters the harbour 
along which we walked in search of whales' bones and shells, I observed an 
appearance new to me, and of some geological interest. Shoals of the American 
' Sand-Launce ' {Ammodytes Americanus), a little fish three or four inches in length, 
had entered the bay, and either seeking a place for spawning or for sheltering 
themselves from their numerous enemies, had run into the shallow water near the 
point, and, according to their usual habit, had in part buried- themselves in the 
sand, wliich they throw up by means of their long pectoral fins. In this situation 
countless multitudes had died or been thrown on snore by the surf, and the crows 
were fattening on them, and the fishermen collecting them in barrels for bait : 
acres of them still remaining, wliitening the bottom of the shallow water with 
their bodies. It was impossible not to be reminded by such a sjiectacle of the beds 
full of capelin in the post-pliocene clay of the Ottawa, and the similar beds 
filled with fossil fishes in other beds as far back as the Old Red Sandstone. 
Geologists have often sought to account for such phenomena, by supposing sudden 
changes of level or iiTuptions of poisonous matter into the water ; but such 
catastrophes are evidently by no means necessary to produce the effect. Here, in 
the quiet water of Gaspe Bay, year by year, immense quantities of the remains 
