Darbishire—Macclesfield Drift-beds. 293 
Whirled along and troken to fragments by the rushing stream which 
received their decaying stems, the ruins of the forest reach the sea, 
and some few pieces float far from shore, beyond the area of depo- 
sited mud and drifted sand. Attacked by xylophagous mollusks, 
and sinking to the ocean-bed, one at least serves as the nucleus for 
organic growth and accretion. Not merely accretion, as in the case 
of an ironstone nodule, which grows more and more regularly ellip- 
soidal in the outer layers round a fern-frond; and not entirely of 
sponge-growth, though some traces of this tissue appear; for it 
would be difficult on this view to account for the reniform envelop- 
ment of the wood. Nor can we admit the idea of the flint being in 
this case secreted into a cavity of the chalk, with this bit of wood 
suspended in the axis of the hollow. But we may perhaps conceive 
that, after being surrounded wholly or partially by organic matter, 
and even buried in the Cretaceous deposit, the wood may have served 
as the local centre of attraction for siliceous solutions, such as have 
more than filled to solidity the tissues of sponges and the cavities 
of Echinoidea, and thus to have undergone the complete ‘ petrifac- 
tion’ through every cell and fibre which is frequently witnessed in 
other wood differently circumstanced. This kind of local attraction 
to particular tissues can be often exemplified in fossil wood which has 
become wholly calcareous, pyritous, or siliceous, just as the whole 
framework of sponge has become siliceous by attraction, continued 
after death, of the same substance which, while alive, it extracted 
from sea-water to build up its spicular skeleton. 
Oxrorp: June 17, 1865. 
II. On THE GENUINENESS OF CERTAIN FOSSILS FROM THE 
MACCLESFIELD DRIFT-BEDS. 
By R. D. Darpisutre, B.A., F.G.S. 
[Read before the Manchester Geological Sede March 29, 1865. | 
At the last meeting of the Society, Mr. Plant made statements 
respecting the supply of so-called fossil shells from the Drift 
at Macclesfield, of a striking and curious character: he warned 
geologists against certain specimens, on the grounds that some were 
only recent “shells sold as fossils, and others, though bearing the 
appearance of Drift-fossils, were not only spurious as such “from 
Macclesfield, but were not even fossils at all, being nothing but the 
results of an elaborate system of importation and manufacture : 
forgeries, in fact, to meet a new demand. Mr. Plant allowed that 
some of these frauds were well calculated to deceive even geolo- 
gists, and quoted a statement that they had been successful at the 
Museums of London, Liverpool, and Manchester. Besides the simple 
introduction of recent shells, he specially reported a process of fetch- 
ing such shells from recent beaches at Liverpool, Southport, 
or Ireland (even the use of West Indian or African shells), the 
breaking-up of the same, and the subjection of the fragments to 
fire or acid, and a subsequent treatment by friction in a basket with 
