JOURNAL AND PROCEEDINGS. 43 
‘ 
CORAL REEFS—MODERN AND ANCIENT. 
Read before the Geological Section of the Hamelton Scientific Assoctatzon, 
Jan. 31st, 1902. 
BY COLa, Ca Co GRAN. 
Despite all that has been written by Darwin, Dana and others, 
including many officers in the Royal Navy, etc., we know little 
which can be regarded as absolutely reliable respecting the rate of 
growth of the modern coral reefs. But far more difficult must it be 
to form anything approaching a correct view as to the time taken to 
deposit a foot of limestone, shale or sandstone 6n the sea bottom. 
One of the best marked Palzeozoic coral reefs ever noticed by the 
writer was close to the southwest point light-house, Island of Anti- 
costi, Niagara series. ‘The rocks named by the Director-General of 
the Canadian Geological Survey, Sir W. Logan, and E. Billings as 
the Anticosti group, are usually thin limestones and shales, but 
at the point stated the upper beds are of considerable thickness, 
very brittle, containing many embedded corals, together with 
immense quantities of crinoid stems, which impart to it a peculiar 
glistening appearance, which you may notice in the mineral Ortho- 
clase. It is often seen in stems or broken plates of crinoids at 
Grimsby. It is quite a mistake to suppose a modern reef (coral) is 
solely built up by coral animalcule. During its formation various 
other things are included in it, and this brings to my recollection a 
lecture on Bermuda by a well-known naturalist. He gravely com- 
menced by informing his audience that the Island was chiefly 
formed from the remains of sea plants. The statement was received 
with ill-suppressed laughter. It is not the less true for all that. 
The Nulliporz plants, of wide distribution and great abundance 
there, possess the property of encrusting the thalli with carbonate of 
lime, extracted from the sea. In Darwin’s Coral Reefs, in section 
first, Keeling Atoll, it is stated on the margin of the reef, close 
within the line where the upper surface of the Porites and of the 
