874 DR B. N. PEACH AND DR J. HORNE ON 



occasional coal-seams; a middle group (Edge Coals), consisting of many valuable coal 

 seams, ironstones, sandstones and shales, with no limestones ; and an upper group, com- 

 posed of limestones, sandstones, shales and coal-seams. This triple classification obtains 

 throughout the midland valley, the lithological and palfeontological types being 

 remarkably persistent. 



The lower group of limestones (Hurlet and Hosies) has been correlated by the late 

 Mr Gunn with the massive marine limestones at Lowick,* Northumberland (Dryburn, 

 Low Dean, Acre and Eelwell), which, as already indicated, are separated from the upper 

 limestone group by the Lickar Coals. (See Plate IV.) If this correlation, which is highly 

 probable, should ultimately prove to be correct, then it follows that the group of strata 

 which, in Northumberland and Eskdale, intervene between the base of the Fell 

 sandstones and the Eelwell and Gilnockie limestones, represents that part of the 

 Calciferous Sandstone in central Scotland which overlies the Cementstone group. It 

 may be further noted that the Lickar and Kilnholm coals are meagre representatives of 

 the valuable series of Edge Coals in the midland valley. (See Plate IV.) 



The triple classification of the Coal-measures at Canonbie adopted by Mr Kidston, 

 from the evidence of the plants, does not obtain in central Scotland. In the latter area 

 only the Lower and Middle Coal-measures are represented : the lower group containing 

 a valuable series of coals and ironstones, and the middle consisting of red sandstones, 

 shales, clays, marls, thin limestones, and poor coals, yielding plants, molluscs, 

 crustaceans and fishes. On the evidence of the plants Mr Kidston correlates this Eed 

 Sandstone group, like that of Byre Burn at Canonbie, with the middle Coal-measures of 

 Enodand.t 



List of Papers Referring to the Geology of the Districts under Review. 



1844. Milne Hume, "Geological Account of Roxburghshire," Trans. Roy. Soc. Edin., vol. xv. p. 433. 



1853. Tate, G., "The Fossil Flora of the Mountain Limestone Formation of the Eastern Borders," in John- 

 stone's Nat. Hist, of the Eastern Borders, p. 290. 



1857. Tate, G., "Anniversary Address to the Members of the Berwickshire Naturalists' Club," Proc. 

 Berwickshire Nats. Club, vol. iii. p. 135. (Read 1853.) 



1857. Embletox, R., " Address delivered to the Berwickshire Naturalists' Club," Proc. Beriviclcshire Nats. 

 Club, vol. iii. p. 219. (Read 1856.) 



1861. Howell, H. H., and (Sir) A. Geikie, Memoir of Geological Survey of Great Britain, "Geology of 



the Neighbourhood of Edinburgh " (sheet 32). » 



1862. Gibsone, E., "The Coal Formation of Canonbie," Trans. North of England Institute of Mining 



Engineers, vol. xi. p. 65. 



* Trans. Geol. Soc. Edin., vol. vii. p. 30G. 



+ We wish to acknowledge the valuable assistance rendered by Mr A. Macconochie and Mr D. Tait in the 

 preparation of the fossil lists embodied in this paper and the list of papers referring to the geology of the districts 

 under review. 



