64 MICROSCOPICAL OBJECTS FOUND 



contain, but almost entirely consist of similar 

 organisms. In their richness, as to number and 

 beauty of species, they almost rival the deposits 

 of the Levant. The greater number of the 

 forms visible to the naked eye are well known 

 to belong to Ehrenberg's family of Plicatilia, espe- 

 cially to the genera Triloculina and Quinquelo- 

 culina. In some localities these abound to an 

 almost incredible extent. Under the microscope 

 we also find Rotalise, Textillari*, beautiful forms 

 of Peneroplis, Calcarinae, Nodosaria?, acicular and 

 triradiate spicula of sponges, small corals, and 

 calcareous prisms of shell structures. The minute 

 cementing portions of the stratum consist chiefly 

 of fragments of the same animals. We find few 

 of the semicrystalline granules which constitute 

 so large a portion of the Barbadoes deposit. If 

 these semicrystalline granules are to be ascribed 

 to the disintegration of the hard corals, such a 

 result was to be expected, a priori, from the rarity 

 of these fossils in the Paris basin, when compared 

 with some of the recent Pliocene strata in the 

 West Indies, in which Madrepora muricata, and 

 other species still found in the tropical seas, are 

 abundant.* The Eocene marl of Pamunkey river, 



* In 1834, Lieut. Nelson, in his paper on the Geology of 

 Bermuda, pointed cut the existence of beds of limestone 



