in the Carboniferous Limestone. 71 
In the Brigsteer section occur all the species characteristic of the 
Arnside Beds, including the giant Chonetes cf. comoides and unusually 
large specimens of Orthotetes crenistria, neither of which occurs above 
this horizon in any section I have examined in the north. Indeed, 
the greater part of the fauna of the bed is strictly limited to this 
horizon, and nearly the same association occurs at the base of the 
Ingleborough succession,! and undoubtedly represents the same horizon. 
Any beds, therefore, below these are of special interest, as they 
carry us well down into C or lower. Such beds occur at Low 
Meathop, opposite Arnside, and at Crag Mollet in the Brigsteer 
section ; in both places they consist of purple dolomitic limestone, and 
contain fine silicified specimens of Syringopora (cf. reticulata) and 
small Cyathophyllids and Seminulas, while at the base at Crag Mollet 
occurs a bed marked by clusters of Diphyphyllum pseudo-vermiculare 
(McCoy). 
If this Diphyphyllid Lithostrotion is to be considered typical of (8), 
then the whole of the Arnside Beds and the Horton Beds will have 
to be included in (S) also. It is possible, however, that we have 
here the forerunner of the Zithostrotion fauna, which becomes so 
characteristic of the Seminula zone above. 
In the Shap and Ravenstonedale district further east the megastoma 
bed is absent, but the same purple dolomitized limestones with 
Syringopora occur towards the base, though they are here much 
thicker and include lower beds than any found at Kendal or Meathop, 
so that at Ravenstonedale we probably have the lowest beds found 
anywhere in the district. The absence of the megastoma bed makes 
the sequence rather more difficult to subdivide, but as the result of 
many years’ work in the district I have come to the conclusion that 
this bed is represented in the Shap area by the sandstone near the base 
of the Ashfell series. 
The evidence on which I rely is as follows:—At Brigsteer, 
immediately beneath the Michelinea bed, we have the Crag Mollet Bed 
full of Diphyphyllum pseudo-vermiculare, which, as far as I am aware, 
has not been found elsewhere at any higher horizon. ‘The same form 
occurs abundantly near the top of the Shap-Ravenstonedale Limestone 
near the base of the Ashfell group, so that the latter should include the 
megastoma bed. 
Again, the base of the Knipe Scar or Melmerby Limestone, resting 
on the Ashfell Beds, is crowded with silicified specimens of Cyrtina 
carbonaria, a form characteristic in the western area of the base of the 
upper Seminula zone; ; furthermore, in the Shap section at the base 
of the Ashfell series, occurs a thin layer enclosing remains of 
Camarophoria isorhyncha, a form characteristic of the very base of the 
lower Seminula zone.® 
Lastly, at Kettlewall, on the east side of the Kendal outlier, we 
have an epitome of the sequence in both areas. Here the megastoma 
bed, very much reduced in thickness, is overlain a few feet above by 
1 See Cosmo Johns & Vaughan: Grou. Maa., 1906. 
2 Dr. Vaughan: Q.J.G.8., vol. lxi, p. 254, footnote. 
3 T. F. Sibley: op. cit., vol. lxii, p. 376. 
