Dr. J. FE. Marv—The Ashgillian Series. 65 
intermediate in age between the Zrinucleus Shales and the Lobiferus 
Beds of Dalarne, the former being of Caradocian and the latter of 
Birkhillian age. The general correspondence of its fauna with that 
of the Ashgillian Beds of Britain indicates its general Ashgillian age, 
but there are certain differences which suggest that beds of other ages 
are also represented in the Leptena Limestone. 
Il. Lirgonogican CHaRAcrers. 
There is a striking similarity in the lithological characters of some of 
the deposits of Ashgillian age over wide areas. Leaving out of account 
the Slade Beds of South Wales and certain deposits which in other 
areas are doubtfully Ashgillian, we find a widespread distribution of 
lower calcareous and upper argillaceous strata. The calcareous division 
in Cumberland, Wales, parts of Scandinavia, and probably elsewhere 
is marked by a greyish, somewhat argillaceous limestone with 
calcareous shales, each weathering olive-green. With these are purer 
white limestones, which often assume a markedly crystalline character, 
as at Keisley and the Chair of Kildare. The overlying argillaceous 
beds are often bluish-grey and not very markedly laminated sand- 
stones. There is a very decided resemblance between these mudstones 
as found in the Lake District, North Wales (Conway), South Wales, 
and in parts of Sweden. 
III. Fosstts. 
The fauna of the Ashgillian Beds is very rich, but comparatively 
little is yet known of it. When the fossils have been collected as 
assiduously as those of the Chalk (for instance) we shall probably find 
a marked contrast between the fauna of the Ashgillian Series and 
those of the Caradocian below and Valentian (Llandovery-Tarannon) 
above. 
In the present state of our knowledge a few notes on the dominant 
characters of the fossils may be of use to future students of these beds. 
In Lakeland and South Wales the abundance and variety of Cystidea 
is very noteworthy. These fossils are specially found in the Stawro- 
cephalus Limestone of the northern area and in the Sholeshook 
Limestone of the Principality. Cystidea of course have a long range, 
but some of those found in the Ashgillian Limestones are probably 
characteristic forms. They appear, however, to be local; for 
example, I am not aware of any record of these organisms in the 
Desertcreate Beds. 
It has been noted above that Strophomena(?) stluriana is characteristic 
of the Ashgillian Beds of the North of England. It is still doubtful 
if this form and Orthis hirnantensis of the Hirnant Limestone are 
specifically distinct. At present we are only able to use the so-called 
Strophomena locally. 
The Slade Beds of Haverfordwest are often crowded with Phyllopora 
Hisingert. The occurrence of this form in the upper part of the 
Ashgill Beds of Backside Beck, near Sedbergh, is of significance. 
The latter beds are worthy of more careful examination.’ 
1 See Marr & Nicholson on ‘‘ The Stockdale Shales’’: Q.J.G.S., vol. xliv, p. 700. 
DECADE V.—VOL. IV.—NO. II. 5 
