published respecting Antrim, Derry, is'c. 35 7 



stances. The "micaceous Limestone found at Toberbelly 

 near Ballycastle, which makes good Lime tor mortar or for 

 manure, and is of the same quaiity with that used at Dal- 

 mully in Scotland," Mr. D. p. 68, jirobably belongs to these 

 measures. The gray Limestov.e commencing at Lough- 

 gall in Armagh, Mr. D. p. 39, is probably that extending 

 to the neighbourhood of Armaiih Town, already mentioned 

 page 281 herein, and belongs to the lower part of the Coal- 

 measures, on the great Basalt and not below it. The notes 

 of Mr. G. represent the Coal-field in Tyrone, a? bounded 

 on the NW, by Limestone at Ruchan ; that Benbervin 

 Castle stands on Limestone near the Blackwater River not 

 far from Clonfecle, and that three or four alternations of 

 Limestone, Freestone and Coal-shale appear, near that place ; 

 that at Desamartin in Derrv, there are very large lime- 

 works in a bluish -gray Rock (not white), and smaller 

 quarries of the sart'.e sort of stone at Cookstown in Tyrone. 

 The Sandstone wliich occurs " between Broughshane 

 and Clough, near the centre of the County," Mr. D. p. 91, 

 probably is the remains of the lower part of the Coal- 

 measures below the Coal-seams ; and so may the same in 

 Rathlin or Raghery Jsland, Mr. D. p. 91, sijice I have not 

 heard of the actual existence of Coal seams there ?, a point 

 on which J wish information, and of their position with 

 respect to the Basalt, if such appear. 



Fifth — Alluvia or Water-moved and v.^orn superficial mat- 

 ters, in yoiu- 33d volume, page J 99, Dr. R. speaking of a 

 tract immediately to the southward of Kells and Connor 

 gays, " we here find a district near four miles in diameter, 

 called the Sandy Braes : over this whole space the basaltic 

 stratification has been carried off, and the operation has 

 reached deep into a very singular substratum, a reddish 

 Breccia, by some mineralogists called a Porphyry, the mass 

 friable,' but the component angular particles of extreme 

 hardness. The Hills, of which this little district is full, 

 are every one perfect segments of spheres, while the loftier 

 basaltic hills that surround it, preserve their characteristic 

 form, to w:t, a gradual acclivity on one side, with a steep 

 abruption on the other." In Mr. D.'s App. p. 33, Dr. R. 

 says that this Breccia is an excellent material for Roads, and 

 frequently ctintains Opal-, at p. -ig, nearly the same is re- 

 peated; to me notwithstanding, the evidence seems defec- 

 tive, of these knowls belonging to any regular stratum, bVit 

 the probability much stronger, of what Mr. D. states, page 

 34 ; viz. that they arc Gravel, (or rather I should say, ruh- 

 ble knowls, the stones being angular, of extraneous alluvia), 



and 



