282 Dr. Mace Culloch on the 
the minutest animals of creation, the foundations of new lands 
are daily preparing under the ocean. Nor, as in the case of other 
submarine formations, are these operations limited to the germs 
of future and distant continents and islands, and destined only 
for the habitations of races in the far remote and merely possi- 
ble future. In consequence of the instincts of these animals, 
assisted by other causes, which will presently be described, the 
rocks which they form become elevated above the sea without 
the necessity of those actions which have raised other submarine 
strata from below. Thus daily additions are made to the habitable 
surface of the earth, and islands gradually arise in the wastes of 
the ocean, enlarging the dominion of man, and promising to unite 
the remotest continents in the bonds of mutual intercourse. 
Independently, therefore, of the proofs which some of these 
islands afford, of elevating forces connected with volcanoes 
acting beneath the surface of the earth, the simple fact itself 
forms an interesting and necessary branch of geological inquiry ; 
and the more so, because it has hitherto experienced unaccount- 
able neglect among geologists. It cannot be less interesting to 
study the formation of immense masses of calcareous rock, by 
living animals, than by the accumulation of the spoils of dead 
ones. Itis in many respects even more so; no less from the 
illustration it affords respecting the ancient calcareous rocks of 
the globe, than from the tangible nature of what, in these 
analogous cases, is only matter of inference, and from the 
apparent feebleness of the agents concerned in the production 
of these most important effects. 
With respect to all the organic fossils, their chief interest is 
derived from the relations which they bear to the existing 
species, and from the effects which they have on the structure 
of the earth. Weare surprised at the immense accumulation 
of shells which form the secondary calcareous strata, or which, 
if they do not actually produce these, contribute most mate- 
rially to their bulk, as well as to their chemical nature: and, 
in examining them, we cannot help being struck with the 
immense additions which the solid crust of the earth has re- 
ceived from the labours of animals which, employed only in 
