Chap. XIII.] 
PERMIAN ROCKS COMPARED. 
335 
however, only to be seen in the counties before enumerated, which lie to the 
north of the River Trent. 
In the north of Ireland the true equivalent of the Magnesian Limestone — 
similar in mineral character and in fossils to the rock in Durham and Yorkshire 
— has been recognized. A small patch of it, occurring at Cultrea, on the south 
side of the Bay of Belfast, was first noticed by Mr. James Bryce * ; and subse- 
quently the fossils were described by Prof. King as species of Schizodus, Myti- 
lus, Area, and Pleurophorus. Afterwards the latter author, examining another 
fossiliferous locality t (Tullyconnel Hill, near Artrea, in Tyrone), observed that 
the parent rock was a sandy dolomite which, like that at Belfast, overlies the 
Carboniferous Limestone, and seems to dip under red sandstone. Among the 
thirteen species of fossils from Artrea, described and figured by King J, Mytilus 
squamosus, Bakevellia antiqua, Schizodus obscurus, Pleurophorus costatus, and 
Turbo helicinus are common to the deposits of the same age in England and the 
Continent, including the far north-eastern Petschora-Land of Russia, whence 
some of those species were brought by my associate Keyserling. The other 
forms, including Corals and Polyzoa, abound in the Magnesian Limestone of 
England. Thus it is now ascertained that the sea in which those peculiar 
animals flourished extended from the eastern to the western extremity of 
Northern Europe, or over a breadth of about 2500 miles ! § 
In comparing the Permian deposits of England with those of Germany, 
it is worthy of remark that, when examined from north to south, the 
mineral masses are, on the whole, found to succeed each other in a similar 
manner in the two countries. Thus, in the English northern counties, it is 
only in Cumberland, Durham, Yorkshire, and Nottinghamshire that we 
meet with the true Magnesian Limestone, or Zechstein, and its associated 
fossils; whilst in Lancashire, Shropshire, Staffordshire, Worcestershire, and 
"Warwickshire the whole group is represented as in Southern Germany and 
Russia, by red sandstones, marls, breccia, and conglomerate, with occasional 
traces only of calcareous matter. The most striking phenomenon, how- 
ever, in regard to this natural group in Great Britain, is its very dissimilar 
lithological character on the opposite sides of the central axis of the country. 
On the eastern side the Magnesian Limestone is the dominant feature, with 
an irregular and evanescent equivalent of the Roth-liegende and a meagre 
capping of red and sandy marl. On the west the lower or arenaceous 
member of the group is largely spread out in Staffordshire, Shropshire, and 
Lancashire ; and there the limestone is for some distance only represented 
by certain calcareous marls near Manchester. The researches of Mr. 
Binney have clearly shown how these sandstones, marls, and conglomerates 
are related to the underlying coal, and how they extend northwards into 
Scotland ; and Professor Harkness and myself have described the vast thick- 
ness of the lower division in Westmoreland (near Penrith), with a central 
representative of the Zechstein or Magnesian Limestone, and a full Upper 
* Journal of the G-eologieal Society of Dublin, | ' On Irish Permian Fossils,' Journ. Geol. Soc. 
vol. i. Dublin, vol. vii. pi. 1. 
t The late General Portloek had formerly trana- § Permian fossils have also been discovered in 
,mitted fossils from this locality to Dublin. Texas, in beds overlying coal-deposits. 
