354 REPORT—1890. 
that direction, but the underground flow to the N.N.W. finding the Cam 
springs; these rise but a few feet after the wettest season, but the varia- 
tion of the water-level in the wells to the south is considerable, the 
maximum difference between the highest and the lowest level being 443 feet 
at Odsey, 78 feet at Barley, and 643 at Therfield; the greatest difference 
in any one year (April to March) being respectively 394 feet (1882-83), 
52 feet (1865-66), and 34 feet (1884-85). Mr. Fordham lias selected for his 
daily record at Odsey the levels on the first of the month, starting April 1, 
the date about which the autumn and winter rains produce the maximum 
elevation. He also gives the mean monthly level per year and per series 
of years. The rainfall returns terminate three months before the well- 
level, viz. on December 31. 
The rainfall year ending three months before the water-level year, 
affords a convenient method of comparison, the effect of the percolation 
of rain being exceedingly slow. The highest level to which the water 
rose was attained twice (50 feet), on March 22, 1881, and February 27, 
1883 ; the lowest level reached, 5} feet, was on December 16, 1884, giving 
a seasonal variation of 445 ; the gr eatest seasonal variation in one twelve 
months was 1882-83, when it amounted to 40 feet (50—10 feet) ; the 
rise was distributed over exactly four months, viz. from October 27 to 
February 27. In 1879 and 1883 the final winter rise was very rapid, 
amounting to 10 to 13 inches in 24 hours in February, or a maximum of 
about half an inch per hour. The summer fall is generally long and 
gradual; in June 1886 an abnormal rise of 8 feet, commencing on May 
25, was due to the exceptional rain of the preceding May, which 
amounted to 4°71 inches. An abnormal summer rainfall of 20°37 inches, 
from April to September 1879, caused the water to rise all the summer, 
culminating in August, and, with a dry autumn, reached its normal 
autumn level in October. The conditions in these cases must have been 
unusual ; the ordinary summer rain, however heavy, percolates but little ; 
much doubtless depends on the amount of moisture held in the air at the 
time. Comparison of the three wells shows close parallelism in the 
curves of movement, but they are later in the deeper wells in Therfield 
and Barley than at Odsey.! 
LANCASHIRE. 
In previous reports, sections were described in the Keuper marls of the 
Fleetwood district, on the east side of the River Wyre, containing 340 feet 
of solid rock salt. The Garstang sandstone to the east has been referred 
to as of Permian age, and referable to the Hawcote sandstone of the 
Furness district. These are said to have been recently bored through at 
Walney Island by the North of England Rock Boring Company, of which 
Mr. Vivian is director, and extensive deposits of rock salt found. It is of 
interest to observe that at the southern horn of Morecambe Bay thick 
salt beds of Keuper Triassic age occur, while similar beds occur on the 
opposite shore of Permian age, and contemporaneous with those of the 
¢@ ‘eee 
east coast between the mouths of the Tees and Tyne. In this relation 7 
the following boring is of great interest, penetrating Permian sandstone 
a few hundred yards east of the salt marls of Presall, and probably 
separated from them by a fault. 
1 Further details and plates wiil be found in the Trans. Herts Nat. Hist. Soc, 
vol, vi. parts i. and ii., July and September 1890. 
4 
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