On the Bituminous Shales of Linlithgowshire, dc. 19 
Some recent piiysico -geographical investigations by Mr 
Hull of the Geological Survey go to prove that speculations 
as to such changes may have an actual foundation in fact. 
In a paper on the position of the arenaceous and argillaceous 
in contrast to the calcareous strata of the Carboniferous 
system of Great Britain,* it is shown on the map accom- 
panying Mr Hull's paper, that they are developed in opposite 
directions ; and that while the Mountain Limestone attains 
a development in solid mass of from 2000 to 3000 feet in 
the Midland district of England, it becomes thinner in 
Northumberland, and mixed with coal seams, while in Scot- 
land it is attenuated to a thickness of only 70 feet. It will 
suggest itself, on examining the map, whether the coal strata 
lying above the marine limestone in Scotland, are not 
really on the horizon of the vast limestone masses of 
England ? The examination of several sections appears to 
confirm this view. Mr Geikie has found in some parts of 
the Lesmahagow district, as well as on the flanks of the 
Cheviots, a remarkable conformity betwixt the Upper Old 
Eed Sandstone beds and the Lower Carboniferous series, f 
They in fact form physically only one formation, — the dis- 
tinction drawn betwixt them on geological maps being 
entirely arbitrary. There is a clear natural demarcation, 
however, betwixt these beds and the Lower Old Eed Sand- 
stones and Silurian shales, which again form only one 
formation. A similar uniformity of the Upper Old Eed 
Sandstone with the Lower Carboniferous series exists in 
Ireland. A closer uniformity in physico-geographical rela- 
tions thus exists betwixt the strata of these two countries, 
than with those of England. 
The Scottish carboniferous strata exhibit the following 
succession of strata in various sections : — First, Immediately 
above the Upper Old Eed Sandstone beds, and conformable 
with them, a series of shales and sandstones of great thick- 
ness : these are distinguished by the Burdiehouse fresh-water 
limestone bed, and in some places the Houston coal-seam ; 
secondly, two or three beds of marine limestone intercalated 
Journal of Geological Society, vol. xviii,, 1862. 
t Ibid. vol. xvi., 1860. 
