Vice-President’s Address. 199 
Mountain Limestone of England is the equivalent of the 
Calciferous Sandstone Series of Scotland. The fact, then, that 
there is some difficulty in referring the Yoredale Beds to 
their equivalents elsewhere, or, even, in drawing a dividing 
line between them and the Mountain Limestone of England, 
is no reason why rocks, whose true position in Scotland is 
known, should be slumped together in order to bring them 
into conformity with the recently proposed Carboniferous 
Limestone Series of England, a term which has admittedly 
been introduced to get rid of a difficulty. 
But, whatever be the position of the Yoredale Beds, the 
Carboniferous Limestone Series of Scotland is a clearly 
defined series, and distinctly separable from the Calciferous 
Sandstone Series on which it lies. This being so, it is very 
unfortunate, to say the least, that the members of the 
Committee who drew up the Report on the Classification of 
British Carboniferous Rocks, should have adopted the term of 
Carboniferous Limestone Series for certain rocks in England, 
the greater portion of which are known to be of older age 
than the rocks to which this term has been previously applied 
in Scotland. 
If the proposal of the Committee be adopted, it can only 
lead to additional confusion in the classification of the Lower 
Carboniferous rocks of Britain. 
The classification given by the Committee in their Table 
of the Divisions of the Carboniferous System as drawn up 
by Professor Hull,’ seems to be founded not on palzonto- 
logical evidence but on the physical conditions which have 
maintained during the formation of the strata,—conditions 
which are not indicative of age, and which have again and 
again recurred at different times. 
'See ante, p. 194. 
VOL. XII. O 
