McB-EKRY —Ecporf OH the " Dingle Bed" Rocks. 233 



by Du Noyer for over three miles. On the high ground of Brandon Mountain 

 folding and undulation of the strata are very apparent. The thickness of the 

 " Dingle Beds " is given in the Survey Memoir as being 10,000 feet. I think 

 this is excessive by a few thousand feet. 



The " Smerwick Beds," which come in regular order below the " Dingle 

 Beds " on the north, on both sides of Smerwick Harbour, and which I include 

 amongst the " Dingle Beds," are stated in the Survey Memoir as being 2,000 

 feet thick. 



There is abundant evidence that overfolding and overthrusting also took 

 place in this region, and in the south-west of Ireland generally, in post-Old 

 Eed Sandstone and post-Carboniferous times. The high angles at which the 

 Old Eed Sandstones lie where they rest on the upturned and eroded edges of 

 the " Dingle Beds " at Sybil Head, and Ballydavid Head, show this ; while the 

 great east and west overthrust fault running from near Headford Station along 

 the Blackwater valley, by Millstreet and Kauturk, clearly indicate a post- 

 Upper Carboniferous overthrust of considerable extent. 



The effect of this overthrust has overridden the lower beds of the Old Red 

 Sandstone on to the Carboniferous limestone and Coal-measures at Millstreet 

 and Kanturk. 



Professor Eeynolds and Mr. Gardiner refer to the evidence of crushing and 

 movement along the line, and in the vicinity of the junction between the 

 " Dingle Beds " and Silurians, to be seen on the coast near Dunquin. This 

 line, as already mentioned, I take to be an overthrust fault junction. Having 

 a fair general knowledge of the Old Eed Sandstone of Counties Kerry and 

 Cork, to the south of Dingle Bay, I do not know of any series of rocks there 

 that correspond with the " Dingle Beds " in general characters ; nor is it con- 

 ceivable that it could be possible to have so vast an unconformability within 

 the limits of the Devonian and Old Eed Sandstone series as that which 

 exists in this area. Even were it possible to admit the Devonian age of the 

 " Dingle Beds," and knowing that we have in the Dingle peninsula at least 

 ■4,000 feet thick of Old Eed Sandstone, which includes a great portion of the 

 lower division of the series, the possibility of their being Devonian is hardly 

 tenable. 



I therefore venture to suggest that my reading of the question, as stated 

 above, is the most natural solution, and that the true position of the " Dingle 

 Beds " is below the Wenlock rocks, and that they are probably of Llandovery 

 age. A strong point in favour of inversion is the following : — The " Smerwick 

 Beds," which are admittedly in their true order below the Wenlock rocks, are 

 undoubtedly part of the " Dingle Beds." In a stream-cutting running from 

 Brandon Mountain to the sea at Doonmore, west of Tidufl', a continuous rock- 



