G. A. Lebour — On the Tenns “ Bernician” and “ Tuedian.” 19 
top than at bottom. Cut back the shale bank a hundred feet along 
the length of the terrace, and another series of pits will begin to 
form, wkile notliing will remain to mark the former position or 
existence of the present line of holes. 
The Ice-hobby has been pretty well ridden of late ; it shifts the 
earth’s centre of gravity, causes the ocean to rise and fall, sinks down 
continents into the molten magma on wliich they float, creeps ont 
from the north over hundreds of miles of flat ; marches over moun- 
tains like nothing, like the old soldier’s nose in the fairy tale; grinds 
to powder the hardest rock, scoops out basins indifferently in soft 
Miocene gravels or crystalline schists, and yet has so little shearing 
force that the upper and linder parts move often in diametrically 
opposite directions ; it eddies round like a Whirlpool in water, turns 
back upon itself with akind of perpetual motion, hollows out combes 
on mountain flanks (and every hill-side that is not convex is a combe), 
and now yields to the soft allurement of a bed of shale. One is 
tempted to ask what feat it will perform next; perhaps it will be 
found to be the cause of wide-spread metamorphism. But we shall 
see. 
Y. — Ox the Terms “ Bernician ” and “ Tuedian.” 
By G. A. Lebour, F. G.S. London and Belgium, F.R.G. S., etc. ; 
Lecturer in Geological Surveying in the University of Durham College of Physical 
Science, Neweastle-on-Tyne. 
\ T the London Meeting of the North of England Institute of 
~\ Mining Engineers last June, I read a paper in wliich I ven- 
tured to put forward a scheine of Classification of the Carboniferous 
rocks of Northumberland which I believed to be both a natural and 
a convenient one. The leading features of this scheme will be best 
understood by glancing at the following table with which my paper 
concluded. 
Table — Correlatixg proposed Dmsioxs with Old Oxes. 
Northümberlaxd, proposed. 
Synoxyms. 
COAL MEASURES. 
Coal Measures. 
Upper 
Car- 
w 
Gaxxister Beds. 
Gannister Beds. 
boniferous. 
3 
( Millstone Grit and 
1 
m 
1 Carboniferous Limestone in part. 
Middle 
^ Car- 
o 
f Toredale Series and 
boniferous. 
j Calcareous Group in part. 
J 
s 
BERXICIAX. 
^ Scar Limestone Series and 
1 
o 
j Calcareous Group in part, plus 
l_Carbonaceous Group. 
0 
Lower 
w 
f Calciferous Sandstone, 
Car- 
j or Tuedian, 
boniferous. 
TUEDIAN. 
^ or Y alentian. 
| and Upper Old Red Conglo- 
(_ merate in part. 
