VOL. XVIII. (2) DEEP BORING AT KEMBLE 185 



A DEEP BORING AT KEMBLE 



BY 

 L. RICHARDSON 



In 191 1 a deep boring was put down from the bottom of 

 the old weU immediately to the south of the pumping-station 

 at Kemble Junction. 



Great-Oolite hmestone, 60 feet thick; beds best des- 

 cribed as " Passage-Beds," 48 feet thick ; Fullers' Earth. 

 73 feet thick; the whole of the Inferior Oolite (as here de- 

 veloped) were penetrated, and the boring was continued into 

 the Cotteswold Sands to a depth of 54 feet 6 inches. 



Great Oolite.— For the first 60 feet the bore-hole passed 

 through pale-yellow oolite of fairly homogeneous structure. 

 A representative piece had a porosity of i6-i per cent, of its 

 volume in addition to the capacity of the fissures in the rock. 



Passage Beds.— The deposits between 60 and 181 ft. 

 down were characterized by a prevalent grey tint. Upon closer 

 inspection, however, it was found that they comprised the beds 

 described in the record given on page 188. They were all 

 practically impervious, and the more calcareous portions were 

 very close-grained. The porosity of a representative sample 

 of the hard rock was only 2-5 per cent, of its volume ; while 

 that of the beds as a whole would be much less, owing to the 

 layers of clay between the stone. 



From a geological standpoint it seems desirable to separate 

 the deposit between 60 and 181 feet down into two portions, 

 and to tentatively denominate the upper 48 feet of deposit 

 " Passage-Beds," that is, Passage Beds between the under- 

 lying and unmistakable Fullers' Earth, and the overlying true 

 Great-Oolite hmestone. 



