THE BRACH/OPODA, 



FEOM THE INFEEIOE OOLITE OF DOESET 

 AND A POETION OF SOMEESET. 



By S. S. BUCKMAN, Esq. 



INGE the publication of Mr. Davidson's very able paper 

 and excellent plates in the first volume of the " Pro- 

 ceedings of the Dorset Natural History and Anti- 

 quarian Field Club," in 1877, a large number of fresh species, 

 some of them new to England, have been discovered. It may 

 be as well to define the extent of the district, and also of the 

 beds, which we propose to review. The Inferior Oolite extends 

 from N.E. to S. W. through Dorset, in a somewhat narrow strip ; 

 but as the border line of the county runs along about the middle 

 of this strip, it has been thought advisable to include a part of 

 Somerset. The part of Somerset, therefore, extends northwards 

 to about Gralhampton, eastwards to Milborne Wick, and west- 

 wards to Crewkerne. The beds reviewed begin with the zone of 

 Harpoceras opalinum, and end with the zone of Cosmoceras Par- 

 kinsoni, this being the extent of the Inferior Oolite, according to 

 nearly all authors. Mr. E. Deslongschamps, however, in his 

 " Brachiopodes Jurassiques," has adopted another system. The 

 beds from the Opalinum to the Sauzei zone inclusive he calls 

 Infra-Oolite Marls, while the zones of Stephanoceras Hum- 

 phriesianum and Cosmoceras Parkinsoni he calls Inferior Oolite 

 proper. This division would do very well for the Oborne Quarry, 

 where the bods below the Humpn*riesianum zone are more or less 

 marly, with bands of stone in between. But at most of the 

 other quarries iu the district the beds below the liuinphriesianuni 



