88 THE OCEAN WORLD. 



deposits of the Gironde, of Italy, and of Austria. The chalk so abun- 

 dant in the basin of Paris is almost entirely composed of Foraminifera. 

 The remains of these creatures are so abundant in the Paris chalk, that 

 M. d'Orbigny found upwards of fifty-eight thousand in a small block, 

 scarcely exceeding a cubic inch of chalk, from the quarries of Chan- 

 tilly. This fact, according to this author, implies the existence of three 

 thousand millions of these zoophytes in the cubic metre (thirty-nine 

 inches square and a small fraction) of rock ! As the chalk from these 

 quarries has served to build Paris, as well as the towns and villages of 

 the neighbouring departments, it may be said that Paris, and other 

 great centres of population which surround it, are built with the 

 shells of these, microscopic animals. 



The sand of the littoral of all existing seas is so full of these 

 minute but elegant shells, that it is often half composed of them. 

 Ehrenberg, the celebrated German microscopist, was recently invited 

 by the Prussian government to assist in tracing the robbery of a 

 special case of wine. It had been repacked in littoral sand only found 

 in an ancient sea-board in Germany. The criminal was thus detected, 

 M. d'Orbigny found in three grammes (forty-six grains troy) of sand from 

 the Antilles, four hundred and forty thousand shells of Foraminifera. 

 Bianchi found in thirty grammes (four hundred and sixty-seven 

 grains) from the Adriatic, six thousand of these shells. If we 

 calculate the proportion of these beings contained in a cubic metre 

 alone of sea-sand, we reach a figure which passes all conception. 

 What would this be if we could extend the calculation to the immen- 

 sity of surface covered by the waves which surround the globe ? 



M. d'Orbigny has satisfied himself, by microscopic examination of 

 sands from all parts of the globe, that it is the debris of Foraminifera 

 which form, in all existing seas, those enormous deposits which raise 

 banks, obstruct the navigation in gulfs and straits, and fill up ports, 

 as may be seen in the port of Alexandria. In common with the 

 corals and madrepores, the Foraminifera are the great agents in 

 forming the isles which surge up under our eyes from the bosom of 

 the ocean in the warmer regions of the globe. Thus shells, scarcely 

 appreciable to the sight, suffice by their accumulations to fill up seas, 

 while performing a very considerable part in the great operations of 

 Nature, although it may not be apparent to us. 



Our exact knowledge of the Foraminifera is of very recent date. 



