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of that, in the lower part of Littondale, is quite consistent 
with what we know of the thickness of the Carboniferous 
Limestone of the district, and it explains in an easy way the 
existence of the Silurian boulders, which otherwise are 
difficult to account for. 
P.S. — The Silurian boulders, now to be seen on the surface 
of the ground, are generally compact, close-grained Silurian 
Grits, similar to the rock of this character which occurs in, or 
near, Bibblesdale. I am not sure of its exact position. 
DEEP MINING AND RECENT ACHIEVEMENTS OF ENGINEERING 
IN CONNECTION THEREWITH. BY WALTER ROWLEY, 
C.E., F.G.S. 
It is sometimes both interesting and profitable to refresh 
the mind, by taking a retrospective view of what has been 
achieved up to the present time, in any of the staple branches 
of industry, especially those branches which constitute the 
foundation, to a great extent, of our country's prosperity 
It is scarcely necessary for me to state that I refer to the 
Coal and Iron trades. 
The writer will endeavour (1) first, to refer to the Early 
Records and Growth of Mining ; (2) secondly, to mention 
the Deepest Mines in Europe; (3) thirdly, the Deepest 
Boreholes ; (4) fourthly, Boring, Sinking, and Winding 
Machinery ; (5) fifthly, Haulage, Lighting, and Signalling ; 
