66 Improvements in Phystcal Science [Jan. 
across the south of Scotland to Dumfriesshire, constituting most of 
the mountains in Peebles, Roxburgh, Selkirk, and Dumfries. They 
appear again’ in Cumberland, and constitute the greatest part of 
North Wales. They occur likewise in Devonshire, about Exeter 
and Plymouth, and constitute the whole of the south of Cornwall, 
as far west as St. Michael’s Mount. These rocks are chiefly grey- 
wacke, transition slate, and lime-stone. The last two rocks con- 
tain petrifactions, chiefly madrepores, and the lowest sea animals. 
Univalve shells have likewise been seen in the lime-stone at Ply- 
mouth and in Dumfriesshire. 
Over the transition rocks lies the old red sand-stone, the first of 
the floetz rocks. It is very abundant in Great Britain. It may be 
traced from Forfarshire with little interruptions, here and there, as 
far as Manchester. 1 believe much further, though I have not my- 
self followed it farther south. Professor Jameson has lately shown, 
that floetz trap rocks occur in it.as a subordinate formation, and 
that the hill of Kinnoul, the Ochils, and part ofthe Pentlands, are 
in reality enormous beds of floetz) trap rocks, situated in old red 
sand-stone. This constitutes an important addition to the Werne- 
rian theory. All the coal-beds in the south of Scotland, and the 
north of England, lie immediately over the old red sand-stone. 
Perhaps, all the coal-beds in England are in the same position, 
though this has not been ascertained. 
The whole of the rocks that cover the coal-beds, constituting the 
floetz formation of Werner, have not yet been determined. The 
difficulty is great, because they are almost entirely covered with. 
soil. But it seems probable, that some of the sand-stone forma- 
tions in Werner’s series are wanting, and there appears to be one 
lime-stone formation which Werner did not find in Germany. The 
chalk lies over the floetz formations of Werner. It is contined to 
the south-east:corner of England. It begins in Wiltshire, runs east, 
and divides into two portions, one of which runs north-east, and 
terminates at Flamburgh Head, in Yorkshire ; the other runs east, 
and dividing, one portion passes by Farnham and Guilford to Dover, 
where it forms the clifis. The other goes along the coast, and ter- 
minates at Beachy Head. 
Over the chalk lie three beds, a bed of sand, the London clay, 
and the gravel which constitutes the surface in the neighbourhood 
of London.. The London clay abounds in marine petrifactions, but 
none have ever been observed in the surface gravel. 
IX. METEOROLOGY. 
1. The most important meteorological discovery, which has 
been made during the year 1815, or indeed for many years, is the 
explanation of the cause of dew by Dr. Wells, in his Essay on 
Dew, the first edition of which was published in the month of 
September, 1814. Dr. Wells has shown that dew very seldom or 
never falls on cloudy nights ; that it is deposited most copiously on 
those substances which radiate heat best, and upon eaclr according: 
s 
