156 THE BATH OOLITE PERIOD. CHAP. 



cycadaceous and zamioid plants occur in the lower and upper strata ; 

 isastrseae and montlivaltise, trigonise and pholadomyse, nerinese and 

 pleurotomarise occupy many of the rocks ; plesiosauri, teleosauri, 

 megalosauri, and ichthyosauri are familiar fossils in almost all 

 stages of the oolites. 



Confining our attention at present to the lower of the three great 

 groups, that of the Bath oolites, we find the most abundant zones 

 of marine life to be collected about the base and the top of the two 

 great masses of calcareous rock the inferior and the great oolite. 

 The principal repository of fossil, mostly land, plants is at the base 

 of the great oolite in Oxfordshire, and toward the base of the 

 inferior oolite in Northamptonshire. Corals, more or less presenting 

 the aspect of a shelly reef, occur near the base of the inferior oolite, 

 as near Cheltenham, and at the top of the great oolite, as at Castle- 

 Combe in "Wiltshire. The lists which follow are founded on one 

 of the richest known districts, that of Gloucestershire ; Oxfordshire 

 having as yet yielded few species, and the Northampton fossils 

 requiring separate enumeration in connection with Lincolnshire and 

 Yorkshire. The Catalogue of fossils in the Museum of Practical 

 Geology, Memoirs of Mr. Hull and other observers to accompany 

 the sheets of the Geological Survey, Dr. Wright's essays in the 

 Palseontographical Society's volumes, and in the Proceedings of the 

 Cotteswold Club, have furnished ample information, and I have 

 made diligent search myself. For the Northamptonshire fossils, 

 believed to be of equal age, but found under different conditions of 

 sea-bed, the latest memoir of Sharp (Geol. Proc. 1870) may be 

 consulted. Morris, Brodie, and Ibbetson have examined the sec- 

 tions of Lincolnshire, and Mr. Judd is now revising the lower 

 oolites, so as to complete the union between the section of Glou- 

 cestershire and that of Yorkshire. 



The first Catalogue includes fossils of the inferior oolite from 

 Gloucestershire, and chiefly from the vicinity of Cheltenham. An 

 asterisk is prefixed to the names of species which have been also 

 found in Northamptonshire. The different parts of the rock in 

 which the fossils occur are marked by the letters 



R. for the Rag beds and upper part of the rock. 

 F. for the Freestone beds in the middle. 

 P. for the Pea-grit and other lower beds. 



