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president’s address. 
Abel, in which the subject is treated both popularly and in 
such a way as to convey much instruction to the general 
reader. Mr. Bagnall, in his paper on “ Flowering Plants 
and Ferns in the County of Warwick,” has been doing 
a service of much importance to the botanist, and one which 
well deserves to be imitated in other counties. Of the 
addresses, too, by the presidents of field clubs, which are 
occasionally published in this periodical, I may especially 
mention that by Mr. Waller, which is full of interest, 
especially in relation to an earthquake of exceptional severity 
which prevailed over the east and south of England, and 
which presented some remarkable features. Mr. Waller also 
draws attention in this address to the change continually 
going on in the composition of minerals, a subject which 
must largely engage the attention of the geologists of the 
future, and modify very considerably the opinions that have 
hitherto been held as to the origin and nature of rocks 
which are called metamorphic. I may, perhaps, be par¬ 
doned in alluding to a paper of my own in the “ Geological 
Magazine” in the year 1863, upon this subject, in which I 
suggested the probability that the great strata of limestone, 
so characteristic of our Silurian rocks, and even beds of coal, 
owe their origin, in a large degree, to a gradual process of 
segregation, carried on through countless ages. We are all 
familiar with the fact that the fossil remains of the strata 
above and below these deposits are deficient, if not quite 
destitute, of the substance which preponderates enormously 
in them. You seldom find a fossil shell with more than a 
mere vestige of the carbonate of lime of which it was com¬ 
posed ; and in the coal measures you see huge trunks of trees 
and stems of plants which, except the thinnest film on their 
surface, have parted with all trace of the carbon which at 
one time made up their entire substance. Its place has been 
wholly taken by the sandstone or shale in which these 
remains are found. A process has been quietly going on 
whereby, without disturbing the most delicate markings on 
their surface, the fossils have parted with the original matter 
of which they were constituted; and this, I would suggest, is 
found accumulated in the strata—in the former case of lime¬ 
stone, in the latter of coal—which is in close proximity to 
the beds which contain them. Take the entire thickness of 
the strata throughout which the fossils and other organic 
remains are distributed ; calculate the mass of carbon or of 
carbonate of lime that must once have entered into their 
composition, and its equivalent will largely be found in the 
adjacent strata, which are now entirely composed of those 
