170 Mr. Griffith, on the Order of Siiccession of the Older 



beds accumulate, the calcareous strata increase in thickness, 

 and at length near the old copper mine of Muckross, the slate 

 beds entirely disappear, and the entire stratification con- 

 sists of limestone, some beds of which are fossiliferous, and 

 contain Producta depressa, variety of the mountain limestone 

 Spirifera bisidcata, Spirifera re&upinata-, and many of the other 

 fossils which usually occur in the lower limestone. 



From Muckross mine the calcareous strata continue with- 

 out interruption, dipping to the south at an angle of 40°, to 

 the base of Turk mountain, a quarter of a mile to the east of 

 Turk cottage, and are still visible at the surface close to the 

 line of the eastern continuation of the fault which is there con- 

 cealed from view by diluvial matter. 



I have been thus particular in describing the strata visible 

 on the north side of the fault at Brickeen Island and Muck- 

 ross, as they present one of the most perfect sections which 

 Ireland affords of the entire suite of the old red sandstone, 

 the yellow sandstone, the carboniferous slate, and the lower 

 carboniferous limestone, and which by their variety form a 

 strong contrast with the uniform character of the chloritic 

 quartzose strata visible on the south side of the fault, which 

 strata evidently belong to the same series as those which oc- 

 cur in a similar position at the Gap of Dunloe, and are in 

 fact a continuation of the same strike. No doubt can there- 

 fore be entertained that these inferior strata form the lower 

 portion of the schistose series of the district to the south of 

 Castlemaine Bay, that they are identical with the chloritic 

 rocks of the Gap of Dunloe, and do not belong to the De- 

 vonian as supposed by Mr. Hamilton *. 



Proceeding to the southward from Turk mountain, the suc- 

 cession of rocks is similar to that already described as occur- 

 ring above the chloritic beds of Dunloe: the strata undulate 

 very much, and present several synclinal and anticlinal axes, 

 so that the upper beds or reddish gray quartzose strata never 

 appear on Turk or Mangerton mountains, and consequently 

 in this line we do not meet with the old red sandstone strata 

 till we approach the northern boundary of the valley of Ken- 

 mare, where it occurs in a line parallel to that already noticed 

 in describing the section between the Gap of Dunloe and the 

 valley of Kenmare. It is true, Mr. Hamilton mentions the 

 occurrence of old red sandstone in the centre of Mangerton 

 mountain, but in that locality he may have mistaken the pur- 



* A section similar to that from the Gap of Dunloe to the summit of the 

 Reeks may likewise be traced from the chloritic rocks, south of the fault 

 at Brickeen Island, up to the old red sandstone on the summit of Glena 

 mountain, as represented in Plate III. fig. 2. 



