80 THE OCEAN WORLD. 



enormous deposits which raise banks, obstruct the navigation in 

 gulfs and straits, and fill up ports, as may be seen in the port ot 

 Alexandria. In common with the corals and madrepores, the 

 Foraminifera are great agents in heli)ing to form the isles which surge 

 up under our eyes from the bosom of the ocean in the warmer regions 

 of the globe. Thus may these little bodies, scarcely appreciable to 

 the sight, suffice by their accumulations to fill up seas, while perform- 

 ing, too, a very considerable part in the great operations of Nature. 



Many beds of the terrestrial crust consist entirely of the remains 

 of Foraminifera. In the most remote ages in the history of our 

 planet, they must have lived in innumerable swarms in the seas of 

 the period ; they buried themselves \\\ the bottoms of the seas, and 

 their shells, heaped up during many ages, now form hills of great 

 thickness and extent. We may say, to give an example, that during 

 the Carboniferous period, a single species of Fusidina has formed in 

 Russia and the United States enormous beds of calcareous rock. 

 Many beds of cretaceous formation are, in great part, composed of 

 Foraminifera, and they exist in immense numbers in the white chalk 

 which covers and forms the vast mountains ranging from Champagne 

 in France nearly to the centre of England. 



But it is to the Tertiary formation that this group has contributed 

 the most enormous deposits. The Nummulitic formation extends 

 from the Alps to the Carpathians; is met with in Algiers and 

 Morocco. In Egypt it was largely quarried for the building of the 

 Pyramids. It is next met with in Asia Minor, and has been traced 

 across Persia, and as far eastward as Bengal and the frontiers of 

 China. The remains of these creatures are so abundant in the Paris 

 chalk, that M. d'Orbigny found upwards of 58,000 in a small 

 block (scarcely exceeding a cubic inch) of chalk from the quarries 

 of Chantilly. This fact, according to this author, implies the 

 existence of 3,000,000,000 of them 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. 



Fig. 12 represents a drawing from Nature, by Messrs. d'Archiac 

 and Haime, of a piece of nummulitic rock, from Nousse, in the 

 Landes, which contains several species of Foraminifers. In the cele- 

 brated quarries of St. Peter,at Maestrecht, the Calcarina cakitrapoides 

 of Lamarck is found in the upper chalk (Fig. 13). In the calcareous 

 formation of Chaussy, in the Seine and Oise district, and other parts 



