140 



THE GEOLOGIST. 



PLANTiE. (?). 



Chondrites acutangulus, M'Coy, Pal. 



Foss. - t. 1 A. f. 5. 

 Palseochorda major, M'Coy, P. F. 1. 1 A. 



I 5. 



minor, M'Coy, P. F. t. 

 1 A. f. 1. 



Brtozoa. (?). 

 Oldhamia antiqua, Forhes, 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. 



Trilobitid^. 

 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.'] 



North Wales & Salop, 



8. Caradoc^ Bala, and 

 Hirnant rocks; sandstones, 

 schists, and limestones : 

 Wales & Shropshire. (Upper 

 Camb^-ian, in part, Sedg- 

 wick.) 



2. Llandeilo and Builth 

 flagstones & schists : Wales, 

 (Upper Cambrian, in part, 

 Sedgwick.) 



1, Lingula flagstones, 

 Stiperstones, Holly bush sand- 

 stone, and Ffestiniog, Tre- 

 madoc, and Arenig slates. 

 (Ffestiniog group, or middle 

 Cambrian, of Sedgwick.) 



Cumberland. 



Coniston grit, 

 with flagstones 

 and limestones. 

 (Upper Cum- 

 brian of Sedg- 

 wick.) 



Chloritic 

 schists and por- 

 phyry. (Middle 

 Cumbrian,Sedg- 

 wick.) 



Scotland. 



Dumfries- 

 shire schists 

 and flagstones. 



Gneissose flag- 

 stones of the 

 North High- 

 lands (?). 



(?) 



Ireland. 



Flags, slates, 

 and lime- 

 stones: Wick- 

 low, &c. 



Schists : 

 Wicklow (?) 



(?) 



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 nscd in these references will be explained by the list of works that will accom- 

 pany a future portion of this Catalogne. 



