M ARR : SECTIONS IN LOWER PALEOZOIC ROCKS. 399 
that of Austwick Beck, (Bed 4 of Sections.) and like it, contains : 
Petraia. 
Phacops elegans. 
Leptaena quinquecostata, &c. 
The occurrence of Phacops elegans, a characteristic May Hill 
form on the continent, now recorded for the first time in English 
beds is quite sufficient to give the date of these beds at Austwick, 
for I have found it at various parts of the Lake District, and also 
in Central Wales, as described by Mr. W. Keeping, (Q.J.G.S., 
1881.) in every case occurring in beds containing graptolites of 
Birkhill type. The lithological resemblance of the beds above and 
below this Phacops elegans zone at Austwick, with the graptolitic 
mudstones and Pale slates respectively, in the Lake District is 
very apparent. 
Finally, the age of these beds is proved by their being suc- 
ceeded conformably by beds of similar lithological character to 
the Brathay flags of the Lake District, and containing the same 
species of graptolites as do those beds. The beds succeeding 
these priodon-bearing flags can also be correlated with the Conis- 
ton flags and grits of the typical area. There is therefore no 
doubt that the unconformity described by Prof. Hughes, as occur- 
ring in the Austwick district, really does occur between the Bala 
beds and the May Hill group. 
In conclusion, the beds from the base of the conglomerate up 
to the base of the priodon-bearing flags are so inseparably bound 
together at Austwick, that they ought certainly to be included in 
one group, similarly the equivalents of these beds in the Lake 
District are grouped together as Stockdale shales, and the pale 
shales of the Stockdale Valley contain fossils of undoubted Birkhill 
type, ( Monograptus lobiferus, M. turriculatus ) thus bearing out the 
classification of Prof. Lap worth, who unites the May Hill beds 
with the pale slates or Tarannon shales, to form one great group 
of the Silurian system. 
