HIND : CARBONIFEROUS ROCKS OF ISLE OF MAN. 1 39 
However, if Zaphrentis Enniskilleni is to be used as a zonal 
form, and hitherto it has seemed always very definitely to in- 
dicate an Upper Dihunophyllum fauna, as I have shown above, 
then we must regard the Derbyhaven beds as high in the Dibuno- 
phyllum zone, a conclusion supported by the apparent identity 
of the coral fauna of all the limestones in the south of the Island. 
It must be confessed that the whole faunal character of the 
Derbyhaven and Castletown limestones is peculiar, and I do 
not know any locality on the mainland with which to compare it. 
Michelinia megastoma elsewhere is most abundant at a lower 
horizon, but a form of this species also occurs in typical Dihuno- 
phyllum beds at Clitheroe. Although the Scarlet beds are un- 
doubtedly of Upper Dibunophyllum age, Dibunophyllids are 
practically absent, and Zaphrentid corals with Cyclophyllum 
are the dominant forms. The latter coral, however, always 
indicates a high horizon. 
At Bradbourne, in Derbyshire, the Zaphrentis beds con- 
tain Prolecanites compressus, and are immediately underlain 
by limestones containing Michelinia tenuisepta in profusion. 
Mr. G. W. Lamplugh, in his masterly memoir on the Geology 
of the Isle of Man, found it impossible to advance on Cum- 
ming's sub-division, and I have nothing to add to his careful 
and detailed work on the stratigraphy of the Carboniferous 
series in the south of the island. Nor could more have been 
done at the time his work was published from the palaeonto- 
logical side. Nearly all the detailed knowledge which forms 
the palEeontological argument now was wanting at that time. 
I was kindly permitted to contribute two pages of palseonto- 
logical notes — pp. 254-256 — to that memoir, in which I drew 
attention to the fauna of the Posidonomya shales, pointing 
out its identity with the fauna which characterises the shales in 
the Bolland and Craven areas of Yorkshire, and the Lower Culm 
beds of North Devonshire, and Germany. I have since that 
date shown that between certain parallels of latitude the shale 
series which succeeds the Visean Limestones always contains 
at its base Posidonomya Becheri and a definite fauna and flora. 
