British Association Reports. 513 
the main shaft. The furnace was the point next visited. Probably 
two tons of fuel were burning in a mass, and the front of the place 
was almost unapproachable within a few yards. The next visit was 
to the stables, where the ponies and horses used in the different 
workings are accommodated. Then the party ascended to terra 
Jirma, upwards of two hours having been spent in the pit. A sump- 
tuous cold collation was provided by the President of the Club, at the 
Fleece Hotel, to which 66 sat down. At Darlington, the interval 
from 6 to 8 was profitably spent at the Albert Hill Ironworks, which 
through the kindness of the managers were thrown open to the 
members of the Club. 
BRITISEL ASSOCTATION REPORTS. 
—>+——_ 
Britiso AssociATIon Reports—SeEcTION C. 
J. On Guractat Srriation. By Prof. J. Pamures, F.R.S, President of the 
Association. 
Q* few subjects amid some apparent differences are geologists 
better agreed than on the general theory of the movement of gla- 
ciers on their inclined beds in the Alps, while on their former and 
permanent effects, as evidenced in the valleys and among the lakes of 
England, the differences of opinion are great. 
The author believed that these differences ought to be brought to 
the test of accurate mechanical principles, as, for instance, the limits 
of effectual pressure to move ice forward on level surfaces and up 
ascending slopes ; and confronted also with accurate notions and 
exact maps of special tracts selected for study. The author then 
described the special phenomena which had been observed by himself 
and Mr. J. E. Lee, of Caerleon, on a swelling ground at the foot of 
the Goérner Glacier. In this case he showed that distinct grooves, 
beautiful striation, and polish, were traceable on broad flat surfaces 
of rock, protected by a shed, 150 feet above the actual bed of the 
Glacier, and about 100 yards from its base. Over this elevated 
tract in former years the Glacier must have passed, and this was 
quite consistent with the known physical constitution of ice and the 
slopes of the ground up which it is capable of ascending. 
It is quite clear that on such ascending slopes the upward move- 
ment of the ice by the continuous pressure of the mass above is a 
real and necessary result. 
The author next described the phenomena of glacial movement in 
Wastdale, and the features of Wastwater, a deep straight lake in 
Cumberland, three miles long. In Wastdale can be shown the reality 
of partial movements of ice in the valley ; but from the great length 
of its lower part and the shortness of the slopes in ancient days, he 
concluded that continuous pressure could not be conveyed through 
the length of Wastdale. He also showed how a study of the relative 
degrees of grinding effected by solid bodies under different degrees of 
pressure, velocity, and inclination of the bed, led to the conclusion 
VOL. II.—NO. XVII. LL 
