SUBDIVISIONS OF THE OOLITE. 413 



corals are found in the great oolite near Bath, and an 

 extended bed of coralline limestone rests upon the freestone 

 of the inferior oolite of the Cotteswold Hills. Figures and 

 descriptions of these corals, which belong, for the most part, 

 to undescribed species from ancient coral reefs, will be given 

 by Prof. Milne Edwards in his forthcoming monograph on 

 the corals of the secondary rocks of England. Numerous 

 crinoideans are met with in the different stages of this 

 group. One genus, the Apiocrinus rotundus (fig. 160), is very 

 characteristic of the Bradford clay. A general outline of the 

 structure and distribution of the echinodermata has been 

 given, in our chapter on Paleontology. The Mollusca are 

 very abundant throughout the entire series, but certain forms 

 characterise many of the stages. Thus Ostrea deltoida is 

 found in the Kimmeridge clay of England and France, and 

 Gryphaa virgula is so abundant in the upper oolites of 

 France that the beds, from this circumstance, are called 

 " Marnes a gryphees virgule." The great oolite of Glouces- 

 tershire has been shown by John Lycett, Esq., to contain 

 a suite of 320 species of Mollusca that are nearly all special 

 to the Bathonian Stage, one half of which belong to the 

 Gasteropoda, and a great many of the species are new.* 

 Some of the most common and characteristic shells of the 

 oolite* are represented in fig. 287.f 



The ferruginous beds of the inferior oolite at Dundry 

 have yielded a beautiful series of well-preserved shells of 

 Mollusca, and those of the Cotteswold Hills contain many 

 well known, and a considerable number of new species . J 



Ammonites and Nautili are very abundant in the different 

 stages of this group. The Oxford clay of Christian Malford 

 has furnished some beautiful specimens of A. Jason, remarkable 

 for having the lateral walls of the aperture prolonged into 

 long spatulate processes (fig. 170). 



Several species from the Kimmeridge clay, and from the 

 inferior oolite of Dundry exhibit various modifications of 

 the processes arising from the aperture of the shell. 



* This beautiful series \vill form the subject of a monograph in the Pal. 

 Soc. publications, by John Lycett and John Morris, Esqs. 



f- From Professor Phillip's Geology, Cab. Cyclopaedia. 



J Copious lists of the fossils from these beds are given in Sir R. Murchison's 

 Geology of Cheltenham, Second Edition, by Messrs. Buckman and Strickland. 



