32 A NEW BOEING AT CAYTHORPE. [Feb. I903, 



varies from 82 to 88 feet per mile (6-inch Map, Quarter-sheet 

 No. 96 S.W., Lincolnshire), and this is on the dip-slope of the 

 Marlstone Rock-bed. A mean dip of 82 feet per mile gave the top 

 surface of this rock at Boring 'No. 5 as 117 feet above Ordnance- 

 datum. The actual datum at which the rock was struck is 111*5 feet 

 O.D., a discrepancy which would hardly allow for a fault. 



(2) There is a good flow of water to the borehole; this would not 

 be the case if such a fault had existed. 



A downthrow to the east, just beyond the boring, might leave the 

 water-supply intact, but it would not help to explain the thick- 

 ness of Upper Lias at the boring ; and although a reversed fault 

 might explain the unexpected thickness of clay, it would have cut 

 off all water-supply from the Marlstone. 



Altogether, then, there does not appear to be anything gained by 

 assuming a north-and-south fault. — H. P., December 12th, 1902.'] 



Discussion. 



Prof. W. W. Watts congratulated the Society on listening to an 

 admirable paper containing several important points carefully and 

 tersely stated. Three distinct points had been made out : — the 

 ' creep ' of the limestone down the escarpment : the washing-out of 

 the Northampton Sands under the creeping limestone • and the 

 development of an extended drainage-area for the springs in front 

 of the scarp. 



Mr. Whitaker remarked that it was a general result of well- 

 sections to increase the known thickness of certain stratigraphical 

 groups. The evidence of ■ creep ' down the escarpment was 

 important. The phenomenon was more common than geologists 

 generally imagined, and he cited in this connection what is 

 happening to the Lower Greensand-escarpment in part of Surrey, 

 where landslips on a large scale are likely to come about sooner or 

 later. He was glad that the Author was taking care to have all the 

 borings in Lincolnshire recorded, and congratulated him on a most 

 valuable piece of work. 



