ON IRISH PERMIAN FOSSILS. 
71 
ance with the views of Griffith and Portlock, as “ New Red Sand¬ 
stone,” and consequently overlying the magnesian limestone; but 
the former may really be older than the latter, in which case it would 
have to be considered as equivalent to the “Rothe-todte-liegende” 
of the Germans. According to this view, the magnesian limestone 
would be a mere patch reposing in a hollow of the red sandstone. 
The section does not take into account the freestone bed found in 
Mr. Slorne’s well, as the locality is a little too east of the line. As 
to whether or not Tullyconnel Hill consists of a similar freestone, 
I candidly confess my inability to come to any positive conclusion 
on the matter. I am in hopes, however, that Mr. M‘Adam, who is 
at present working out the geology of the Artrea and surrounding 
districts, will succeed in obtaining sufficient data to enable him to 
settle the question. 
The absence of coal-measures (a patch of which occurs near Annag- 
hone, not much more than a mile to the south of Tullyconnel) in the 
section may be attributed to denuding agents having removed them 
before the deposition of the magnesian limestone; but I cannot re¬ 
frain from hazarding the suggestion, that there runs through Tully¬ 
connel Hill an enormous fault, which has thrown down the car¬ 
boniferous limestone, coal-measures, and magnesian limestone far 
below their original level. A somewhat similar phenomenon occurs 
at Cullercoats and Whitley, on the coast of Northumberland, a little 
north of the Tyne, where the celebrated ninety-fathom dyke has 
thrown down the “ Rothe-todte-liegende,” marl slate, and magnesian 
limestone; thus preserving these members of the Permian System as 
an outlier, wedged in among the coal-measures. 
With the exception of Colonel Portlock’s “ Report on the Geo¬ 
logy of the County of Londonderry, and of parts of Tyrone and Fer¬ 
managh,” 1843,1 have not been able to consult any works referring 
to the geological structure of the Artrea district. Probably Dr. 
Griffith may have noticed it in some of his Reports. In his Geolo¬ 
gical Map of Ireland, however, the district in question has the co¬ 
louring of “ New Red Sandstone,” which leads me to suppose that the 
“ fossiliferous dolomite” has been overlooked, or included in the Sa¬ 
liferous System. 
Colonel Portlock’s “ Report” contains a notice which evidently 
refers to the Tullyconnel Permian deposit. Speaking of the coal- 
measures and mountain limestone of Annaghone, the Colonel ob¬ 
serves :— u And a little to the north, geologically overlying the 
