Vol. 58.] THE FOSSILIFEROUS SILURIAN BEDS OF KERRY. 259d 
more than any other beds in the district. As they are entirely 
surrounded by peat and alluvium, their relation to the other 
Silurians cannot be ascertained. 
TIT. Correxation oF THE ExposurEs, AND ConcLusIoNns 
AS TO THE GENERAL SUCCESSION. 
If the theory with regard to the structure of the Clogher Head 
inlier which we have adopted is correct, the three series which we 
have described as A, B, and C are repetitions of one and the same 
set of deposits, and it should be possible to correlate and compare 
the several bands. This we have attempted to do in Table I 
(p. 254), but the subject is beset with numerous difficulties. The 
newest beds are easily correlated: in each ease we have a thick 
series of slates and grits followed, after an intervening green ash, 
by a thick series of red sandstones and ashes, and then by a band 
of greenstone succeeded by a thick mass of rhyolite. 
The chief difficulty les in the enormously thick series of calca- 
reous sandstones and flags (C9): for there is nothing in the A or 
B series comparable to this in thickness. At certain horizons in 
the band (C9) too, fossils cf distinctly Llandovery type occur ; 
while neither A nor B has yielded fossils clearly of Llandovery age. 
These Llandovery fossils are, however, assuciated with many 
others of Wenlock type, and hence we do not feel justified in 
definitely styling these beds Llandovery, but call them Wenlock- 
Llandovery. The non-representation of the Wenlock-Llandovery 
Beds in the A and B series may be due to their being cut out by 
the big fault at Owen; or it may be that further search will disclose 
the fact that fossils of Llandovery type do actually occur in the 
older beds of the A and B series. A further difficulty is to decide 
where to draw the line between the Ludlow and the Wenlock Series. 
The officers of the Geological Survey regarded a well-marked green 
ash (A 2, B 2, C 3), which occurs in each limb of the fold, as the 
top of the Wenlock Series, and considered that the overlying 
beds, which, as a rule, contain few fossils but worm-tracks, are of 
Ludlow age. Irom the fact, however, that fossils of Wenlock type 
occur in the worm-track-bearing grits and flags (B1), we were 
compelled to include the beds and their equivalents (A 1) and 
(C2) in the Wenlock Series. The beds which should succeed 
(A.1) and (B1) are cut off from them by faults. In the C series, 
however, at Trabaneclogher, after a small area where the succession 
is obscured by blown sand, we meet with a series of beds (C 1), 
the age of which it is by no means easy to determine. They contain 
worm-tracks, but no distinctively Wenlock fossils, and lithologically 
resemble. the Croaghmarhin Beds, which are clearly of Ludlow 
age. We therefore feel justified in grouping these beds with the 
Ludlow Series. 
The correlation of series C and D iseven more puzzling than that 
of A, B, and C. We believe that the following table (p. 256) 
represents the relationship :— 
