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THE GEOLOGIST. 



II. Roestone, or true oolite. 



III. Freestone. 



IV. Oolite marl. 



V. Gryphite grit, 



VI. Cidaris sand. 



2nd. Stonesfield slate. 



In studying these beds the more conveniently, and with 

 the greatest success, we shall, of course, commence our 

 research with an attentive examination of the escarpments 

 which are presented to our view on their western side, as 

 from the fact of their strata dipping from the west to the 

 east, we are enabled to do so with the greatest facihty; and 

 when we have indubitably ascertained the position of the 

 pisolite, we shall find little difficulty in tracing up the over- 

 lying beds in the order before noted. But it is frequently 

 a difficult matter to determine the situation of the pisolite, 

 on account of the debris with which the escarpment is 

 covered, as well as from the displacement of large masses 

 of the pisolite itself from its normal position; and these two 

 causes frequently lead the geologist, when examining this 

 district, to the conclusion that the Cotteswold hills are 

 composed entirely of oolite, when this rock only forms 

 about one-third of their height. In order, then, to satisfy 

 ourselves upon this point, it is necessary to examine, 1st, 

 the direction of the dip, and 2ndly, the position of this 

 bed with respect to the underlying one. If the dip be from 

 west to east, at an angle of about 120°, and it is found 

 superimposed upon the yellow clay of the upper lias, we 

 have then the right starting-point from which to commence 

 the study of the oolite. 



It is the more necessary to attend to these circumstances, 

 as at one hill in this neighbourhood we have the pea-grit 

 occurring at the bottom of a quarry (near the base), and 



