THE PORTLAND OOLITE. 359 



occurrence in many of the beds. The slabs con- 

 taining the Goniopholis, previously described, have 

 numerous teeth and scales of the Lepidotus minor 

 scattered among the bones. 



The Portland Oolite.* — The series of sedi- 

 mentary deposits, termed the Oolite formation by 

 English geologists, and known as the Jura lime- 

 stone on the Continent, from the mountain-range 

 in which it is so largely developed, consists of 

 Limestones, sands, and clays of great thickness and 

 extent, which abound in marine shells, corals, 

 crinoidea, articulata, and fishes — terrestrial and 

 marine reptiles, insects, and land plants — and two or 

 three genera of very small mammalia, referable to 

 the marsupialia and insectivora. In this formation 

 there are several local intercalations of fluviatile 

 deposits, resembling the Wealclen in the presence 

 of terrestrial animals and plants, and freshwater 

 shells. -j- Certain beds of the Oolite (called the 

 Stonesfield slate) contain organic remains, which, 

 with the exception of trigoniae and other marine 

 shells, correspond with those of the Tilgate cal- 

 ciferous grits. The collocation of teeth and bones 



* The term Oolite, or egg-stone, is derived from many of the limestones 

 being composed of an aggregation of very small grains or spherules, which 

 bear some resemblance to clusters of small eggs, or to the roe of a fish ; this 

 structure is merely concretional. 



t See Wonders of Geology, vol. ii. p. 436. 



