22 G. A. Lebour — On the Tenns “ Bernician ” and “ Tuedian.” 
that part of Britain in which the beds which it denotes are most 
largely developed, where especially the cliaracters marking the 
series elsewhere are found associated, as, I believe, they are nowhere 
eise. There numerous beds of limestone represent the massive 
calcareous mass of Derbyshire ; there occur the Coal-bearing beds 
of Bussia and the Posidonomya Becheri shales of the Culm ; there 
the sandstone and grit facies of the Series is most strongly developed ; 
and there finally are the palaeontological characters of the Silesian, 
Belgian, and Scotch series blended in an almost unique manner. 
These are all qualities which eminently fit Bemicia to be looked 
upon as a type locality or region. In the second place, the name 
“ Bernician ” gives rise to no preconceived notion that experience 
can prove untrue, it expresses a geographical truth and nothing more. 
Dr. Woodward and Dr. Karl Mayer evidently intended to include 
evervthing between the Millstone Grit and Devonian under the term 
“ Bernician,” wliereas in the paper to which I have already referred, 
and which was purely local in character, I retained the name 
“ Tuedian ” for the Calciferous sandstone series. I, however, also 
showed that the line of division between Tuedian and Bernician 
was a variable one, that the one series ran into the other as it were, 
and that moreover the base of the Tuedians (in which I include the 
so-called Upper Old Eed Conglomerate) in a similar manner ran 
into the Old Bed, and was not sharply divided frorn it. The former 
of these points I again urged more strongly at the Glasgow Meeting 
of the British Association in September last. The question left to 
be decided is this : — Is “ Bernician ” to be distinct from Tuedian, 
or is it to contain it as a subordinate member? This is not an easy 
question to answer at present, but I incline to think that the last 
will be nearer the truth, and that in time the Tuedians will come 
to be looked upon as passage-beds from Old Bed to Bernician, parts 
of which may be claimed by both. 
The word Tuedian which I employ is in rnuch disfavour in 
Scotland. The only objections to its use that I have heard, however, 
are, — first, that the “ Cement-stone and red-sandstone series” occurs 
throughout all the Carboniferous distriets of Scotland, and is in the 
Lothians much more typically developed than in the Tweed Basin ; 
and. secondly, that the name “ Calciferous sandstone series ” given 
to these rocks by Maclaren in 1839 is a good one. 
To the second objection it may be at once replied that as a purely 
lithological term of necessarily only local application, exception 
might well be taken to Maclaren’s name even were it not so 
dangerously similar to the Potsdam “ Calciferous series ” of North 
America, or even to our Oxfordian “Calcareous grit.” The first 
objection is a stronger one, but it does not show that “Tuedian” is 
a bad name — only that a better might be invented. If a better 
one had thus been proposed before 1S55, so much the better; but 
“ Tuedian ” came out then, and if not the best possible is yet a 
geographical name, and not a bad one in itself ; is it not better to 
retain it, whatever the classificatory value of the beds which it 
represents may prove to be ? 
