46 
form nearer the perpendicular. Thus the different hades in 
the varied deposits may he accounted for. 
Throws are described as being due to a thicker deposit 
taking place on one side of a vein than that on the opposite 
side. The north and south vein, just cited, will answer to 
show the mode of explaining the throws. The rising of 
heated water, from the top of the fissure, would not only 
oppose the falling of the sediments, but would collect and 
carry them upwards and away from the perpendicular to 
the east. The sediments, thus gathered and lifted, would 
fall on the underlying side of the fissure. Under such con- 
ditions, the underlying side would build up faster than the 
overhanging one, and would, after a period of continued 
deposition, attain a higher level. This higher level of the 
underlying side is in agreement with a very general law 
respecting metalliferous veins and faults. Thus throws may 
begin at nothing, in deep lying rocks, and continue to aug- 
ment upwards until they ultimately become very con- 
siderable. 
Shifts and bent positions of the strata, like the throws, 
are considered as beginning from nothing, and as being 
mostly accomplished during the contemporaneous building 
of the veins and strata. Without the aid of diagrams, 
justice can scarcely be done to an explanation of the mode 
of operation; but the most noteworthy characteristic con- 
ditions are, the powers of evolving heat along the courses 
of the several veins, and the agencies of numerous complex 
marine currents. 
PHYSICAL AND MATHEMATICAL SECTION. 
December 7th, 1869. 
E. W. Binney, F.R.S., F.G.S., President of the Section, 
in the Chair. 
“On the Mean Monthly Temperature at Old Trafford, 
Manchester, 1861 to 1868, and also the Mean for the Twenty 
Years 1849 to 1868/’ by G. Y. Vernon, F.R.A.S., F.M.S. 
