﻿G. A. Lehour — On the Terms " Bernician " and " TuecUan." 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, while nothing 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 which they float, creeps out 

 from the north over hundreds of miles of fiat ; 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 tliat the upper and under parts move often in diametrically 

 opposite directions ; it eddies round like a whirlpool in water, turns 

 back upon itself with a kind 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 sliall 

 see. 



V. — On the Terbis " Beknician " and "Tuedian." 

 By G. A. LEBOtTB, F.G.S. London and Belgium, F.E.G.S., etc. ; 

 Lecturer in Geological Surveying in the University of Durham College of Physical 

 • Science, Newcastle-on-Tyne. 



AT the London Meeting of the North of England Institute of 

 Mining Engineers last June, I read a paper in which I ven- 

 tured to put forward a scheme 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 — Correlating proposed Divisions with Old Ones. 



Northumberland, proposed. 



Synonyms. 



O 



o 



Pi 



Ph 



COAL MEASURES. 



Gannistee Beds. 



Millstone Grit. 



Coal Measures. ) Upper 

 [ Car- 

 Gannister Beds. ) boniferous. 



( Millstone Grit and ^ 

 \ Carboniferous Limestone in part. Middle 



1^ n^,. 



m 

 o 



Hi 



BEENICIAN. 

 TUEDIAN. 



f Yoredale Series and 

 Calcareous Group in part. 



] Scar Limestone Series and 

 1 Calcareous Group in part, plus 

 L Carbonaceous Group. 



f Calciferous Sandstone, 

 1 or Tuedian, 

 ■{ or Valentian, 

 1 and Upper Old Bed Conglo- 

 (^ merate in part. 



boniferous. 



Lower 

 - Car- 

 boniferous. 



