536 On the Fossil Fishes of the Carboniferous Limestone Series of Great Britain. 
aud Connemara, the limestone is interleaved with shales and sandstones, with 
occasional beds of thin coal. In Ireland as well as England the limestone rests on 
the denuded edges of silurian grits and slates, sometimes with the intervention of 
conglomerates or sandstones, sometimes without. In each the limestone is very 
thick and massive in the central portions of its area, and their northern and southern 
portions become intercalated with beds. ot shale and sandstone, which gradually 
increase in thickness towards the boundary line, the limestone at the same time 
becoming thinner bedded and finally disappearing. 
The Carboniferous Limestone in Scotland cccupies the lowland country between 
the Grampian Mountains and the border hills, The series is divided into two 
parts—the Lower or Calciferous Sandstones, and the Upper or Carboniferous Lime 
stone. The former consists of an extremely irregular series of sandstones, shales, 
limestones, and thin beds of coal, about six hundred feet in thickness.. The Car- 
boniferous Limestone series is composed of alternating beds of shale and sandstone, 
with several layers of thin limestone. The greatest development is at Beith, in 
Ayrshire, where the limestone is about forty feet im thickness. Beds of clay-ironstone 
are of frequent occurrence, especially in the upper portions. The Northumberland 
district resembles that of the Scottish group to a large extent ; they are composed 
almost entirely of sandstones and shales, with occasionally thin limestones and coals. 
In the:district around Armagh, from which the majority of the fish remains 
described in the preceding pages have been obtained, the Carboniferous Limestone 
series overlie the grits and slates of Lower Silurian age, the equivalents of the Bala 
or Carodoc Beds of Wales ; the series consists of — 
Upper Limestone, 
Calp or Middle Division, 
Lower Limestone, 
Sandstones. 
Lower Silurian. 
R. Callan. Armagh. SE. 
N.W. 
Fic. 1. Section From 8.E. or Armacu, to N.W. or Benpurs Caste. 
a, Silurian strata. c. Calp or Middle Series. e. Permian Beds. 
b. Lower Carboniferous d. Upper Carboniferous 7. Bunter Sandstone. 
Limestone. Limestone. g. Drift. 
Horizontal scale, 1} inch to 1 mile. Vertical scale, 43 inches to 1 mile. 
