﻿178 BRITISH FOSSIL TRIGONI^. 



The exact position of the shelly hemisphcErica bed of the Saiiton section is perhaps 

 rather doubtful, probably it should be referred to the Northampton sands, nearly at the 

 base of the formation. 



(See series of comparative vertical sections, of members of the Lower Oolites, by J. 

 W. Judd, 'Mem. of the Geological Survey of England and Wales, Rutland, &c.,' Plate I.) 

 A most comprehensive and instructive series of sections drav/n to a scale of one inch to 

 fifty feet. 



The Museum of the Royal School of Mines has a varied series of specimens of 

 T. hemisphcerica, from the Cotteswolds, from the district of Rutland, from South 

 Lincoln, and from North West Lincoln. A large Cotteswold specimen is in the geo- 

 logical museum of the University of Oxford. The collections of Dr. Wright, Chel- 

 tenham ; Mr. Witchell, Stroud ; Mr. S. Sharp, Northamptou ; Rev. J. E. Cross, 

 Appleby, and my own cabinet also, fully illustrate its several aspects. 



It appears to be absent in the Inferior Oolite of Northampton, Oxford, Somerset and 

 Dorset ; neither has it been recorded at any foreign locality. 



1 In the foregoing description I have expressed the conviction long since entertained by me, founded 

 upon a comparison of fossils of Lincolnshire limestone with those of the Oolite Marl and subjacent beds in the 

 Cotteswolds, that the fossil fauna of the two deposits are identical, and differ only in species which inhabited 

 the variations of sea bottom, such as may be expected to occur in a deposit which extends from the estuary 

 of the Severn to that of the Humber broken only by the upraised portions of Oxfordshire and Northamp- 

 tonshire. 



The general scope of this monograph will not admit of any detailed comparisons between the fauna of 

 widely separated deposits ; it may, however, be useful to indicate a few typical forms which by their 

 considerable extension laterally connect the more distant deposits. At both localities the Ammonites are 

 almost absent. 



Amongst the Gasteropoda will be found the gigantic Nutica LecJchamptonensis, which is rare 

 near to Stroud and to Cheltenham, but reappears abundantly in South Lincolnshire, and is well exemplified 

 in the Grantham Museum ; it is also present in the limestone at Appleby, exemplified in the collection of 

 the Rev. J. E. Cross. 



Of the Conchifera, Li7na hellula. Lye, formerly obtained in the Nailsworth Valley at Culverhill in 

 considerable numbers in a quarry long disused, is specially deserving of notice ; it retains its colour par- 

 tially preserved ; examples are now in the Museum of the Eoyal School of Mines. As the rock of this quarry 

 is extremely hard the stone is not employed commercially and the shells are rare. A small specimen of 

 the species obtained by Professor Morris in the limestone of the Ponton cutting, South Lincolnshire, was 

 figured in the Great Oolite monograph of this Society, vol. for 1853, pi. iii, fig. 9. More recently it has 

 been found in South Lincolnshire, with the colours partially preserved. At the north-western extremity 

 of the County at Appleby it is met with abundantly in a beautiful condition, in tint a dull purple with 

 narrow concentric zones of cream colour ; specimens marking all stages of growth import a peculiar 

 aspect to the Limae in the collection of the Rev. J. E. Cross. 



Of Brachiopoda the characteristic Terebratula fimbria of the Cotteswolds is found to have disappeared 

 in the limestone of Lincolnshire ; it retains the accompanying T. submaxillafa, Dav., which is also locally 

 abundant in the Cotteswolds ; at Appleby the specimens are peculiarly large, surpassing the Cotteswold 

 forms. 



In contrast to the general accordance of species of Conchifera which exists between the Lincolnshire and 



