[pages 3-4]

Mr. Charles Darwin, in his valuable work on "The Structure and Distribution of Coral Reefs," has explained, with very great accuracy, all the conditions under which coral reefs are now forming in the Pacific Ocean. The conditions are precisely those which will explain all the phenomena of the limestones of Devonshire. Upon the theory that the land around which coral reefs have been formed has been gradually subsiding, and that during the subsidence there has been a constantly upward growth of the reef-constructing corals, this observer explains the progress of coral formation in some cases, and the destruction of the coral animals in others.

He has shown us at what depth the polypifers can exist, and how slight movements destroy them. Not only is the sea active in grinding up the coral rocks, and thus forming deposits, but "the number of the species Holothuria, and of the individuals which swarm on every part of these coral reefs, is extraordinarily great; and many ship-loads are annually freighted, as is well known, for China, with the trepan, which is a species of this genus. The amount of coral yearly consumed, and ground down into the finest sand, by these several creatures, and probably by many other kinds, must be immense. These facts are, however, of more importance in another point of view, as showing us that there are living checks to the growth of the coral reef, and that the almost universal law of 'consume and be consumed,' holds good even with the polypifers forming those massive bulwarks which are able to withstand the force of the open ocean."

By these means there was a formation of material which was eventually to receive a slaty structure; and if to this condition we add the by no means uncommon one of volcanic action pouring out its molten matter, to produce the all-involving trap rocks, the entire set of phenomena is complete.

Such then are the geographical, geological, and physical condition of the Devonshire limestone, we must now return to the economic value of these stones. […]

R. Hunt.