COU^'TY OF STIELING. i47 



llixers. 



The principal river connected with Stirlingsliire is the Forth. 

 Its source is a spring on the northern side and near the top of 

 Ben Lomond. The stream is, for the first eight or ten miles of 

 its course, called the AVater of Duchray; then it enters Perth- 

 shire, passing under the name of Avondhu, or the black river; 

 after which, returning to Stirlingshire, it assumes the more 

 familiar name of the Forth. It is a dark and sluggish stream, 

 very unlike any ordinary Scottish river, and in its noiseless 

 meanderings resembling the Xorthumbrian river Till. Winding 

 round the base of Craigforth, near Stirling, it receives from the 

 north side the clear waters of the Teith, and is joined by the 

 Allan just opposite the town. Below Stirling the river, increased 

 in dimensions by the tide, is curiously zigzag in its movements, 

 forming what are called " the links of the Forth." From Alloa 

 eastward it becomes an estuary, and is known as the Firth of 

 Forth. The Carron rises in the interior of the county, and, 

 flowing eastward, joins the Forth at Grangemouth. The 

 Endrick, a fine fronting stream, rises about the centre of the 

 county, and flows westward through a finely-wooded valley, 

 with a good deal of arable land, into Loch Lomond. The other 

 streams are the Avon, the Kelvin, the Blane, the Devon, and 

 the Bannock. 



Geology. 



Geologically, the county of Stirling is in the centre of the 

 great midland valley, which is bounded on the north by the 

 Lower Silurian rocks, rising into the rugged schists and gneisses 

 of the Hiohland mountains, and on the south bv the same rocks, 

 as developed in the contorted greywackes and shales of the 

 southern ui)lands. The substratum of the valley is the Lower 

 Old Led Sanilstone, which is exposed in the east of Scotland from 

 Stonehaven to the Firth of Tay, and thence extends south-west- 

 ward across the island to the Firth of Clyde. It contains abund- 

 ance of igneous rocks, among which the Ochil Hills are con- 

 spicuous. Along the southern flank of the Ochils the Lppcr Old 

 lied Sandstone ]>revails, till it is overlapped by carboniferous 

 strata. The volcanic material which is develo}»ed at the top of 

 the Old L'ed Sandstone, or base of tlie carboniferous series, is 

 exhibited in the long chain of heights stretching fi'om the 

 Cnnijtsie Fells to the south of Arran. To the lower half of the 

 carboniferous system belong the rocks on which the town and 

 castle of Stirling are built. Near Stirling are the Touch Hills, 

 which are continued westward by the Gargunnock and ]*'intry 

 Hills, and across the Endrick by the Killearn and Canijisie Fells. 



