380 Dr. H. A. Nicholson on the Genus Climacograpsus. 
a well recognized and hh current form an altogether dubious 
and undeterminable specie 
sm h a 
t, Scalariform Snc sane of G. colonus, Barr., from the Coniston Grits 
near Sedbergh. 6, Another specimen rof the pets from the same loca- 
h the 
and cell-partitions; from a specimen from the base of the Coniston 
Flags, west side of "Long Sleddale. e. Ordi nary lateral view of a frag- 
ment of G. colonus, Bar, showing the qut dentales; from the Coniston 
Grits near Sedbergh. All considerably enlarged. 
oc. Skiddaw Slates (upper beds): Thornship Beck, near 
sie Ellergill Beck, near Milburn} Lower Llandeilo: Ty- 
obry and oiher localities i in Wales. Upper Llandeilo : every- 
where in the Anthracitic Shales (Moffat Shales) of Pe south 
of Scotland, and in numerous localities in North ánd South 
Wales and in Ireland. Caradoc: common in the Mudstories 
of the Coniston series of the north of England. Lower 
dovery: Haverfordwest (collected by Prof. Harkness). 
Climacograpsus bicornis, Hall. 
Graptolithus sores: Hall, Pal. New York, vol. i. p. 268, pl. 73. — u— 
Diplogra pne ne is, Carruthers, Am, & Mag, at. Hist. Jan. Lino 
A central solid axis is present; but this does not appear to be 
ever produced, either proximally or distally, beyond the frond 
to any thing like the extent observable in C. Hs acer re 
regards the characters of the base, four distinct forms may be 
distinguished, though it is not clear whether these should be 
