420 
THE LAST DECADE. 
the openings leading to tlie shaft. Mr. Fairley, by means of a vane- 
anemometer fixed to the top of the closed well, was able to ascertain 
the amount of air which passed in and out of the wells in a given 
time ; and in one instance at Salberg, between July ?.rd and July 6th, 
he found that with a rise of the barometer of "4 inches an under- 
current of 1176 millions of cubic feet In the following year Mr. 
Fairley obtained a large dry gasometer, constructed to pass 3,000 
cubic feet per hour, and coupled this to his pipe at the top of the 
well, and frequent readings were taken. The residts corrobo- 
rated his former experiment, and demonstrated that the currents 
var}^ in nature with the changes of the barometer, just as the volume 
of the air in any closed reservoir varies strictly with the atmos- 
pheric pressure when the influence of temperature has been eliminated. 
Hence the observations were considered to prove the existence of 
large cavities or fissures in the underlying strata adjacent to the 
wells. In the case of the well at Salberg, this cavity has a capacity 
approximating to ten million of cubic feet, which would occupy a 
chamber two hundred and seventeen feet in length, width, and height. 
Mr. Joseph Lucas contributed an interesting account of the 
vestiges of ancient forests, which formerly covered the moors in the 
neighbourhood of Nidderdale ; and a paper on some sections in the 
lower pala30zoic rocks of the Craven district was read by Mr. J. E. 
Marr, in which an unconformity was shown to exist at the base of 
tlie Mayhill beds, occurring between the Mayhill and Bala beds, 
occurring at Crummack Beck Head in Craven. 
Previous to the year 1859, Mr. Jackson, of Settle, ^Ir. Farrar, 
and Mr. Denny, (formerly secretary of this Society), had conducted 
explorations in the Dowkabottom Cave, near Kilnsey, the results of 
which were described in the proceedings of this Society for that year. 
In 1865 a further contribution to the subject was made by Mr. Farrar 
and Mr. Denny, and from that time to the year 1881 no further 
investigations were made. During the summer of 1881 Mr. E. B. 
Poulton and a number of gentlemen from Oxford spent a portion of 
their vacation in a further exploration of the cave, the results of 
which are published in the proceedings for that )^ear. The cave is 
described as consisting of a series of chambers connected by narrow 
