102 PROCEEDINGS OF SOCIETIES. 



" i. Yellow sandstone, limestone, and shale, 

 "n. Lower limestone. 



"in. Impure argillaceous limestone, called calp, black shale, and 

 sandstone. 



" iv. Upper limestone.' ' 



3. " Lower Limestone. — This division forms by much the most ex- 

 tensive portion of the series in Ireland. In the northern counties of 

 Fermanagh, Cavan, Leitrim, and Roscommon, it is in part covered by 

 the upper division of the series, but in the midland and southern coun- 

 ties, with the exception of the calp valley of the counties of Dublin, 

 Meath, and "Westmeath, it forms the surface rock throughout the greater 

 portion of the limestone country." 



4. "Calp, or black shale series. — The name 'calp' was given by 

 Mr. Kirwan'to the black argillaceous limestone of the neighbourhood of 

 Dublin, which alternates with black shale, and contains flattened sphe- 

 roids of pyritous clay ironstone. In some districts the lower beds of 

 this series consist of alternations of sandstone, shale, and limestone, 

 more or less pure ; in others, the sandstone is wanting, but the upper 

 beds in all consist of thin, alternating beds of impure limestone and 

 shale. In some localities the lower beds, in addition to the sandstone 

 and shale, contain indications of carbonaceous matter ; and impure beds 

 of coal, varying in thickness from half an inch to two inches, have been 

 observed : which circumstance, as in the case of the yellow sandstone, 

 has led to so many fruitless trials for coal." 



5. Page 10. — " The thickness of the calp series, where fully deve- 

 loped, is very considerable. On the north-west coast of the county of 

 Leitrim it exceeds 1700 feet ; though in the county of Cavan, between 

 Belturbet and Ballyconnell, it is not more than 400 feet." 



6. Page 11. — "This division is much more fully developed in the 

 northern districts of the Carboniferous Limestone than in the midland or 

 southern ; and it was solely from the clear exhibition of their strata, as 

 seen in the precipitous cliffs of the remarkable Carboniferous mountain 

 district of the counties of Sligo, Fermanagh, Cavan, Leitrim, and Eos- 

 common, that the subdivision of the series has been attempted." 



7. Page 11. — "The calp and shale division is, perhaps, best deve- 

 loped on the west coast of the counties of Leitrim and Sligo, between 

 Ballyshannon and Benbulben. In this line of section, the strata dip to 

 the southward at an angle of from 2° to 5° from the horizon. The lower 

 limestone of Ballyshannon is succeeded by beds of black shale, contain- 

 ing balls of clay ironstone interstratified with impure argillaceous lime- 

 stone. These beds continue as far as the parallel of Bundoran, where 

 they are succeeded by a series of alternations of gray, and occasionally 

 reddish-gray sandstone and black shale, with argillaceous limestone. 

 Some of the sandstone beds contain casts of Calamites enveloped in 

 coaly matter ; and some thin but irregular beds of coal have been ob- 

 served, though none worth working have been discovered ; and from 

 the nature of the country it is improbable that any such do exist. 

 These beds are succeeded by alternations of black shale, with impure 



