268 UXDERGROUXD WATERS OF XORTH-WEST YORKSHIRE. 
slied into the Ciummack valley. This is doubtless partly due 
to the direction of the master joints in the limestone, but is 
])robably also due to the jiresence of a subterranean ridge of 
impervious rocks of Silurian and Ordovician age which runs 
across Crummack Dale in an E.S.E. and W.X.W. direction 
and which if continuous would pass between Gaping Ghyll 
and Long Kin East. 
The exact conformation of this ridge beneath the limestone 
will be better understood by reference to Pis. XXVI. and 
XL., and Fig. 3 (p. 256). 
Five cwt. of ammonium sulphate was introduced into a 
sink on The Allotment (P 10). about 500 ^^ards X.E. of Long 
Kin East, on June 9th. at 3 p.m.. and this reappeared at Aust- 
M'ick Beck Head on June 22nd. having taken 13 days to accom- 
plish the journey. X'one of the other streams were affected on 
that day, but on the 24th and 25th two small streams in Clapdale 
which had previoush^ shown iri'egularity (see pp. 265-6) as regards 
their ammonia percentage were again slightly variable, but 
for reasons previously exjilained no importance was attached 
to this. 
P 11 and P 12 on The Allotment are usually dry, and have 
not been tested, but from the results obtained at the Shooting 
Box Stream immediately to the north it is obvious that their 
waters must flow to Austwick Beck Head (S 28). 
A stream which rises on the southern slope of Simon Fell 
[PI. XXVII.] sinks at P 16, passes through a thin limestone, 
re-emerges at S 37, and flows past the Shooting Box on The 
Allotment. 
On June 9th of the same year 1 lb. of fluorescein was poured 
into the stream which flows past the Shooting Box and then 
passes through the wall and sinks at the extreme southern end 
of Fell Close (P 14) near the Bench Mark 1320.1 (6 inch Ordnance 
Map). 
Of this no trace was found, and consequently the experiment 
was repeated on June 26th. 1903, when 2 lbs. of fluorescein 
were put in. 
All the springs from Austwick Beck Head to Turn Dub 
were watched for a period of ten days b}^ members of the 
