450 
Mr. C. Lapworth on the Geological 
representative of the Bala group, that the Upper Llandeilo 
forms of Scotland predominated in the highest Oaradoc rocks 
of Westmoreland, and that in Bohemia they passed up unal¬ 
tered far into the rocks of the Third Fauna. In the face of 
such startling discoveries, he could not fail to reach the con¬ 
clusion that either the enormously extended vertical range of 
the various Graptolitic species was out of all proportion to that 
of the species of the Brachiopoda and Crustacea, or else that 
our knowledge of the fossils in question was so defective that 
no reliance could be placed upon it. In either case the result 
was the same : the Graptolites were clearly valueless as ex¬ 
ponents of the geological age of their containing beds. 
The Moffat Series . — The special point upon which former 
theories of the geological range of the British Graptolites may 
be said to have turned was the distinct reference, by Sedg¬ 
wick and Murchison, of the richly graptolitic Moffat series to 
a systematic place inferior to that of the Bala Limestone of 
North Wales. It is the complete disproof of this erroneous 
view that has had the most important intluence in determining 
the current of recent research in this direction, as it has neces¬ 
sitated a searching review of the supposed consentaneous evi¬ 
dences upon which former theories were founded, with the 
result of effecting a marked revolution in many of our pre¬ 
vious opinions. 
To the hasty investigator these remarkable Moffat rocks 
appear to be merely a few local bands of black graptolitic 
shales imbedded in a vast thickness of barren greywackes. 
Their small vertical extent, and their peculiar physical rela¬ 
tions, naturally led all their original investigators to consider 
them as of very insignificant importance. I have shown else¬ 
where*, however, that these Moffat beds (instead of forming 
a single deposit of subordinate geological value, and affording 
a heterogeneous fauna subject to great local variations, as 
generally believed) actually embrace three successive forma¬ 
tions paleontologically distinct, and of an importance approxi¬ 
mating to that of the so-called formations of Siluria. Not 
only has each of these three formations everywhere a collective 
fauna peculiarly its own, but the majority of the graptolitic 
species that characterize it have a very restricted range within 
it. In the same way it has been made clear that, instead 
of belonging wholly to the Upper Llandeilo, only a fraction 
of the Moffat series can, with doubt, be assigned to that sub¬ 
formation, its two higher formations representing most dis¬ 
tinctly the Caradoc and the Lower Llandovery. 
Quart. Journ. Cteol. Soc. vol. xxxiv. p. 240, <&c. 
