Kinahan — On Irish Arenaceous Rocks. 1& 



Associated with the sand dunes, and at times within them, are 

 peculiar thin-bedded horizontal friable calcareous sandstones, suit- 

 able for farm walls. The mode of formation of these horizontal 

 sandstones is hard to conjecture, as they seem to have been origi- 

 nally seolian drift, which is not horizontally bedded. They seem 

 to have been cemented from the outside inwards, as in places the 

 middle parts of the beds are uncemented : on these the wind acts, 

 and consequently the sandstone is very much tumbled about. 



TYRONE. 



Douglas Bridge, eight miles south of Strabane. — The stone 

 here has been extensively used for cut-stone purposes in Strabane, 

 and in Letterkenny, Co. Donegal (twenty-seven miles distant) ; 

 easily worked ; stones all dressed in the quarry. 



"WEXFORD. 



With reference to the epitome of the geology of this county, 

 we may take this opportunity of adding the following, which is 

 of special interest. 



Baginbun, N.N.W. of Baginbun Point, on the coast S.E. of 

 Fethard, are conglomerates which dip N.N.W., and appear to lie 

 unconformably on greyish and blackish slates and grits, which dip 

 S.S.E. at high angles. In one bed graptolites were found; but 

 further south are conglomeritic slaty rocks, unlike any of the Ordo- 

 vicians of the county, but very similar to some of the Cambrians^ 

 especially those at Ferrycarrig, N.W. of Wexford town (g. s. m.). 

 Some of the early explorers considered the Fethard conglomerate 

 to be the base of the Ordovician ; but the graptolites in the beds 

 below it were considered fatal to such a conclusion. What has now 

 been ascertained in the Co. Donegal may suggest a solution, as 

 these dark beds with graptolites, between the Fethard conglomerate 

 and the Baginbun beds, may belong to a portion of the Arenigs. 

 If the existence of Arenigs can be proved here, it would, perhaps, 

 also suggest that farther north a band of similar rocks may have 

 extended obliquely north-eastward from Killurin and Ferrycarrig 

 to the sea, having to the northward and southward the typical 

 Oldhamia-bearing Cambrians. The beds in the neighbourhood of 

 Ferrycarrig are very similar to those at Baginbun. 



