442 ME. L. EICHAEDSON ON THE INPEEIOE OOLITE [JSToV. I907, 



from the Clypeus-Grit in contact with those clays the usual fossils 

 were obtained. 



The high ground, situated principally to the north-west of the 

 spring just noticed, is largely composed of the black-speckled rocks, 

 which have been worked in several places. The higher Great- 

 Oolite Beds come on to the south-east, and are magnificently 

 exposed at Grove's Quarry, Little Milton. 



IV. Conclusion. 



There are several points of similarity between the Bath-Doulting 

 and the Bissington-Burford districts : both districts are near lines of 

 country along which movements of upheaval were frequent during 

 the time of formation of the Inferior -Oolite rocks. As a result, 

 in the former district, up to a line at a certain distance from the 

 Mendip Hills, the Upper Trigonia-Giit rests on the Upper Liassic 

 deposits without any intervening rocks ; and nearer still the ' Grit ' 

 is overstepped by the Doulting Beds, which, in the immediate 

 neighbourhood of the Mendip Hills, rest upon the Carboniferous 

 Limestone. 



The Doulting Beds are equivalent to the Ctypeus-Grit of the 

 Eissington-Burford district, the Bubbly Beds to the Eubbly Beds, 

 and the Anabacia-L\mest<mes, together with the Doulting Stone, 

 to the ' Massive Beds.' Clypeus Agassizi is the characteristic 

 echinoid of the Yallis - Doulting Stone, Clypeus Ploti of the 

 Clypeus-Grit of the Bissington district. Probably these fossils 

 afford an example of parallel development : they passed through the 

 various phases of development in their respective districts, and con- 

 temporaneously became morphologically analogous, in part doubtless 

 in response to the analogous environment. So also with Holec- 

 typus liemisphcericus and H. depressus. Whereas over a considerable 

 portion of the Bath-Doulting district there is Upper Trigonia-Giit, 

 and in places Dundry Freestone and Upper Coral-Bed, between 

 the Doulting Beds and the Upper Lias, in the Eissington-Burford 

 district there is no such deposit — the Clypeus-Grit rests directly 

 on the Upper Liassic clays. 



The dates suggested for the Doulting Beds apply also to the Clypeus- 

 Grit. Above the Doulting Beds in the Midford area is the Fullers' 

 Earth, the lower portion of which, at all events, is of zigzag 

 hemera. There is also a clay-bed, although thin, in the neighbour- 

 hood of Eissington : but its precise date is not quite certain at 

 present. 



It should be noticed that there is no deposit between the clay 

 and the Eubbly Beds of the Clypeus-Grit. 



When the Clypeus-Grit is traced westwards, other beds are seen 

 to come in between it and the Upper Lias. Between Bourton-on- 

 the-Water and Wotton-under-Edge the intervening beds attain 

 a considerable thickness ; but their total thickness varies at different 

 places, for they are thicker on the Cleeve-Hill plateau than at Birdlip, 



