Nodces of Memoirs — Underground Waters, N. W. Yorks. 75' 



form a ridge running in an approximately nortb-west and south-east 

 direction, and unconformably overlain by the Carboniferous Lime- 

 stone. If this line be continued it separates the Gaping Ghyll to 

 Clapbam Beck Head flow from that of Long Kin East to Austwick 

 Beck Head. Thus it appears that this ridge of Silurian rocks forms 

 an underground water-parting, which the Committee hopes to bo 

 able to ti'ace for a considerable distance across the area. 



The magnitude of this undertaking will be to some extent realized 

 whfn it is stated that upwards of 400 samples of water have been 

 tested for common salt, ammonium, and fluorescein, making in all 

 upwards of 1,200 tests. The whole of the grant of £40 has been 

 spent upon the investigation, and a small sum in addition. The 

 experiments which have been carried out have indicated which are 

 the most suitable reagents for use in difi'erent cases, and it is 

 consequently hoped that future investigations will be carried out 

 at rather less cost than has been the case up to the present. The 

 Committee ask to be reappointed, with a grant of £50. 



IL — The Underground Waters of North-West Yorkshire.'^ 

 By Rev. W. Lower Carter, M.A., F.G S., Hon. Sec. Under- 

 ground Waters Committee, Yorkshire Geological and Polytechnic 

 Society. 



Part I. The Sources of the Aire. 



T 



Malham are traversed by two branches of the Craven Fault with 

 the downthrow to the south. Malham Tarn lies on Silurian, and 

 its overflow sinks in the limestone directly the northern fault i» 

 crossed. The drainage of the area to the west of the Tarn 

 disappears at the Smelt Mill Sink. The drainage of the area east of 

 the Tarn is carried off by Gordale Beck, along the course of which 

 some water sinks into the jointed limestone. To these three sinks 

 correspond three principal outlets, the stream at Malham Cove, 

 Aire Head Springs, and the springs at the bottom of Gordale. 



The history of previous investigations is then given. From the 

 centre of Malham Cove a dry limestone gorge runs in a northerly 

 direction to the Tarn. Up to the beginning of this century flood- 

 waters were known to traverse this valley and discharge over the 

 Cove. There are several sinks along the line of this dry valley. 

 Now all the overflow is taken by three sinks south of the Tarn. 



Yarious efforts have been made to trace the connection between 

 the sinks and outlets. Flushes of water from the Tarn have been 

 shown to aff'ect Aire Head before Malham Cove. Experiments by 

 introducing chaff, bran, magenta, and uranin into the sinks failed to 

 show any traces at the outlets. 



The present investigation was carried out during 1899, by a 

 Committee of Engineers, Chemists, and Geologists, appointed by 

 the Yorkshire Geological and Polytechnic Society. Flushes of 

 water were sent down from the Tarn to the Tarn Water Sinks. 



* Read before the British Association, Section C (Geology), Bradford, Sept., 1900. 



