HUGHES : mGLEBOROUGH. 
369 
All the varieties of lithological character observed in the 
basement bed of the Silurian under Ingleborough may be seen 
in the corresponding position in other districts, especially im- 
mediately to the north of Ingleborough, in Hebblethwaite GiU, 
and other sections in the same district east of Sedbergh. In 
Skelgill, behind the Bowness Hotel at Windermere, it is repre- 
sented by a thin, tough calcareous bed, with a few pebbles in it 
here and there. In North Wales a similar hard banded rock, 
with a few patches of pebbles, mark the base of the Silurian in 
Nant Caweddau, near Corwen, and in this the only fossil found 
was Favosites alveolar is. The Hirnant Limestone is the exact 
counterpart of the crystalline basement limestone at Crag Hill. 
Tracing the base of the Corwen grit by Cyrnybrain, on the west 
of the Dee Valley, we find coarse white grits, with Meristella 
crassa, Petraia subduplicata, P. crenulata, and other fossils, which 
connect this horizon with the Lower May Hill or Llandovery 
Beds, which form the base of the Silurian in South Wales. At 
Blaenycwm, near Llandovery, a similar thin conglomerate forms 
the basement bed of the Lower Llandovery. With all its palae- 
ontological and lithological variations, we have in the Austwick 
Conglomerate a very persistent horizon represented, and one 
well worth further close examination. 
There is a palaeontological question which wants further 
elucidation. In the description of the fossils of the Hirnant 
Limestone, McCoy described a flat, finely-ribbed brachiopod, 
which occurs abundantly at that horizon, as an Orthis, and 
named it 0. Hirnantensis. When I was tracing the base of 
the Silurian in the Sedbergh district I found a fossil much re- 
sembling McCoy's 0. Hirnantensis in shape and external mark- 
ings in the black shales of Fairy Gill and elsewhere in that dis- 
trict. But the mapping led me to assign the beds in which it 
occurred to a lower horizon than that to which I was incUned 
to refer the Hirnant Limestone. I had the good fortune to have 
as my frequent companion in the field the Kev. H. G. Day, the 
Head Master of the Grammar School, a keen palaeontologist, 
and with him made a large collection from the Fairy Gill shales, 
and found that the fossil which so strongly resembled McCoy's 
Orthis Hirnantensis had the valves turned over like a Strophomena, 
