Vol. 54.] COEALLIAN EOCKS OF UPWARE. 605 



west on the same farm, beneath the peat ; little importance, however, 

 can be attached to the statement, as both Gault and Kimeridge Clay 

 rest upon the flank of the Corallian ridge farther south. 



Prof. Bonney remarked long ago that the core of blocks of the 

 Upware oolite was often greyish-blue. Certain fossils in the 

 Woodwardian Museum show a similar matrix. There seems no 

 doubt that such was once the colour of all the Upware oolite, 

 its present buif colour being the result of oxidation. The oolite 

 from this well is, however, less pure than the higher beds. A 

 solution of a small piece of this grey oolite in hydrochloric acid gave 

 a considerable residue of bluish-black mud, which, when dried, 

 formed a clay indistinguishable from the lumps in the limestone. 

 In this grey oolite I estimated carbonate equivalent to 91" 5 per 

 cent, of carbonate of lime. The colour of the rock would then seem 

 to be due to finely-divided particles of bluish-black clay, when 

 not oxidized. The result of a similar estimation of the Northern 

 Quarry oolite showed about 95 per cent, of carbonate of lime, but 

 this estimation was not quite satisfactory and the percentage 

 should probably be slightly higher. 



The surface of the ground at this well lies perhaps 3 feet above 

 river-level, somewhat higher than the floor of the Northern Quarry. 

 In the lane about 400 yards south of the Northern Quarry very 

 white oolite is seen in a ditch, almost certainly a higher bed than 

 any in the Northern Quarry ; for the slope of the ground is decidedly 

 greater than the slight northerly dip in the ditch and in the quarry ; 

 and the dip is probably fairly constant about here. On the whole, 

 it seems that the thickness of the oolite of the Northern Quarry 

 and its neighbourhood could scarcely be less than 40 feet, and may 

 be considerably more. 



As already mentioned, the stratigraphical relationship of the 

 oolite of the Northern Quarry to the Eag of the Southern Quarry 

 was long a matter of uncertainty, and perhaps even now it is not so 

 surely fixed that additional evidence is superfluous. The grounds 

 on which earlier writers have placed the Northern Quarry oolite 

 below the Rag have been mentioned above. The following points 

 have been brought out so far in the present paper in support of this 

 correlation : — 



(1) The fauna of the oolite of the Southern Quarry is inter- 



mediate in character between that of the Rag and that of 

 the oolite of the Northern Quarry, and contains many 

 species of each not found in the other. 



(2) Beneath some 40 feet of oolite, as seen in the well at 



High Fen Parm and in its neighbourhood, there is in 

 the well not only no indication of Rag below, either 

 lithologically or palaeontologically, but, on the other hand, 

 there are signs of the proximity of clay. The bluish-grey 

 oolite of this well is decidedly less pure than the Rag. 



Al hough there is no evidence known to me of diminution of the 



