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First. The diversities of composition of the strata composing 

 these hills is very great. The argillaceous beds of the Lower 

 Lias, Marlstone, and Upper Lias, form an impervious floor, on 

 which have been built up the friable or slightly consolidated 

 Sands, the rocky beds of the Inferior Oolite, again succeeded 

 by the nearly impervious Fullers Earth, capped by the rocky 

 beds of the Great OoUte and Forest Marble. 



The variations in the amount of the deposits are well known 

 over the extended area of the whole range of the Cotteswolds, — 

 the Sands being estimated at 100 feet or more in thickness at 

 their western edge, as at Cam Down, and at 15 feet or so 

 beyond Stow; the Inferior Oolite estimated at 264 feet at 

 Leckhampton, and at 25 feet at Bath ; the Fullers Earth 200 

 feet near Bath, and as an inconsiderable band of Clay east of 

 Cheltenham. All these thinnings out of strata are clearly 

 perceived in their passage across the area under consideration, 

 and exercise some importance in forming in their aggregation 

 the relative heights of the hills in various parts of the district. 



I ascribed the Physical Geography of this district to be due, 

 in the second place, to inequalities of elevation or depression of 

 the strata. In order to ascertain what inequalities exist, I 

 have, by the aid of the Geological map, and by taking a large 

 number of measurements with a delicately constructed Aneroid 

 barometer, prepared several sections of this district, but on the 

 present occasion will only mention two of them. In these 

 sections I have endeavoured to lay down the position of the 

 junction of the Sands with the Upper Lias, because of its 

 important bearing on the water system of the district, and 

 because this horizon is generally readily determined, being weU. 

 marked on the hill sides by the outburst of springs; and at 

 present I will confine my remarks to this junction hne. 



The first section is on a line extending from Haresfield, over 

 Standish Beacon, and in the direction of the general dip of the 

 strata of the Cotteswold range — namely, to the S.S.E. Just 

 under the Beacon a fine spring of beautifully clear water (which 

 probably supplied the Eoman camp) indicates the position of 

 this junction line, and here it is at an elevation of 500 feet 

 C 2 



