172 Anaij/sis of Scientific Books. 



pose, wliile they are almost horizontal in the middle of the 

 basin; finally, the structure of tliis formation, as Werner ex- 

 presses it, shews that it is independent of the ordinary series of 

 formations which compose a mountain-chain. This coal for- 

 mation is parcelled out in tattered fragments, which occupy the 

 lowest grounds of the country, without any mutual con- 

 nexion among its parts. Thus, while in the above district 

 we see it fill up an immense valley, between primitive and 

 transition mountains, there exists, towards the Murray 

 Firth, one of these coal districts set down, as it were, in 

 the midst of the primitive chain ; and to the south we find 

 another in the transition mountains of the north of England. 

 Following the sea-shore northward from Berwick, we meet at 

 Siccar Point, the southern limit of the coal formation of Scot- 

 land. The sea has here laid open the precise point where the 

 rocks of this formation join with the transition grauwackes of 

 Lammermuir. Whatever is to the north of the base of these 

 hills belongs to the coal formation, which extends over all the 

 low districts of the counties of Haddington, Edinburgh, Stirling, 

 Kinross, and Fife, and which is united in the county of Lanark 

 to the coal formation of the counties of Dumbarton, Renfrew, 

 and Ayr, which fills the basin of the Clyde. An approximate 

 idea of the northern limit of this formation may be had, by 

 drawing a line in the direction from north-east to south-west, 

 from Stonehaven, a small sea-port in Kincardineshire, where 

 Mr. Playfair placed the junction of the primitive and secondary 

 rocks, to Callender, in Stirlingshire, where, by Mr. Necker's 

 observations, we pass from one of these formations to the other. 

 The coal formation of Edinburgh is separated from the grau- 

 wacke of Lammermuir by a narrow stripe of red sandstone, to 

 which formation probably belong the sandstone of Hawthornden, 

 near Roslin and that of Craigmillar Castle, as well as the conglo- 

 merate of the Siccar Point. This same sandstone formation is 

 found on the northern limit of the coal country, where it re- 

 poses also on the transition rocks ; for in the first chain of the 

 Grampians we observe likewise grauwacke and a rock of quartz, 

 feldspar, and chlorite, Avhich appears to belong to the transi- 

 tion class ; but this stripe is inconsiderable, and is sometimes 

 altogether absent. 



A striking feature is still wanting to this geological portrait. 

 Above the coal region, which has been described as an immense 

 basin, whose surface, little elevated above the level of the sea, 

 is relieved merely with rounded hillocks, there rises at uncer- 

 tain distances conical hills, or ridges of naked and precipitous 

 rocks, of a nature totally different from the ground on which 

 they repose. The rocks which form these hills, whose height 

 vanes from three hundred to seven hundred and sixty feet, 

 are basalts, wackes, grunstein, and other rocks of the same 



