140 
THE GEOLOGIST. 
Plants. (?). 
Chondrites acutangulus, M'Coy, Pal. 
Foss. " t. 1 A. f. 5. 
Palseochorda major, M'Coy, P. F. 1. 1 A. 
f. 5. 
minor, M'Coy, P. F. t. 
1 A. f. 1. 
Bryozoa. (?). 
Oldhamia antiqua, Forbes, Sil. 28. 
radiata, Forbes. 
Annelida. 
Arenicolites didyma, Salter, Geol. Jour, 
xii. 248. 
sparsus. Salt., Geol. Jour, 
xiii. 
Histioderma Hibernicum, Kinahan, 
Dubl. G. J. vij. 184. 
TRILOBITIDiE. 
Palseopyge amsayi, Salter, Geol. Jour, 
xii. 249. 
Localities : Skiddaw, Longmynd, Wicklow, and Wexford. 
B. Lower Silurian (Murchison) ; Middle and Upper Cambrian (Sedgwick.) 
[Upper Cambrian and Lower Silurian, Lyell and Phillips ; Tremadocian, 
in part, and Snowdonian, Woodward.l 
North Wales & Salop. 
Cumberland. 
Scotland. 
Ireland. 
3. Caradoc, Bala, and 
Hirnant rocks ; sandstones, 
schists, and limestones : 
Wales & Shropshire. (Upper 
Cambrian, in part, Sedg- 
wick.) 
2. Llandeilo and Builth 
flagstones & schists : Wales. 
(Upper Cambrian, in part, 
Sedgwick.) 
1. Lingula flagstones, 
StiperstoneSjHollybushsand- 
stone, and Ffestiniog, Tre- 
madoc, and Arenig slates. 
(Ffestiniog group, or middle 
Cambrian, of Sedgwick.) 
Coniston grit, ~1 
with flagstones j 
and limestones. 
(Upper Cum- 
brian of Sedg- 
wick.) J 
Chloritic 
schists and por- 
phyry (Middle 
Cumbrian, Sedg- 
wick.) 
Dumfries- 
shire schists 
and flagstones. 
Gneissose flag- 
stones of the 
North High- 
lands (?). 
(?) 
These present variable mineral characters, being chiefly clayey and 
sandy sediments, with occasional calcareous bands, especially in the 
upper or Bala series. In the lower beds fossils are few ; with the 
increase of the calcareous constituent the organic remains are more 
abundant. 
The period of the formation of these deposits was marked by enor- 
mous outbursts of igneous rocks, such as porphyry, syenite, greenstone, 
and some probably of submarine origin, as the sedimentary felspathic 
and volcanic ashes of earlier date. There igneous rocks are often 
interstratified with the beds, and sometimes much altering them. 
Similar rocks are not wanting in the lower Cambrian series. 
' The abbreviations used in these references will be explained by the list of works that will accom- 
pany a future portion of this Catalogue. 
