Mr Menteath on the Geology of Nithsdale. 31 9 



considerable supply from England, since the navigation of the 

 Nith has been improved. 



Lying to the eastward of the valley of Sanquhar, in the grey 

 wacke mountains, are the great lead- mines of Wanlockhead and 

 Leadhills. The former are in Dumfriesshire, and the property 

 of the Duke of Buccleuch ; the latter, belonging to the Earl 

 of Hopetoun, are in Clydesdale. The principal ore at both 

 places is galena or lead-glance, which is found in great quanti- 

 ties. Specimens of many of the more beautiful and rarer of the 

 spars of lead are met with ; * and, of late years, mineralogists- 

 have described new species of lead spars as natives of these 

 mines. Silver is contained in the lead, and about 7 or 9 oun- 

 ces of it can be extracted from the ton. In 1809, the pro- 

 duce of the mines of Leadhills was 25,000 bars,^-of Wan- 

 lockhead, 15,000 bars, each weighing 9 stones avoirdupois, and 

 the price being L. 32 the ton, the gross produce exceeded 

 L. 80,000 in that year. Since that period, I believe the an- 

 nual returns have been far below those of the year 1809- They 

 must, however, since they were opened, have yielded millions 

 of revenue. 



Gold is found in the sand of the streams in the vicinity of 

 these mines. By washing the sand, the miner in his leisure 

 hours collects a small quantity of this precious metal. It is said 



Bald, may be considered as about 18 cwt., and, therefore, in each acre there 

 will be about 22,000 tons of coal. But, deducting even Jth for pillars left in 

 working the coal, which is the utmost ever lost, we shall have of coal for use 

 16,600 tons in each acre. 



Now, it has been ascertained from accounts of the sales, that not more than 

 13,000 tons are annually required for the whole district. One square acre 

 would therefore supply this demand for one year and a quarter ; and, conse- 

 quently, the 20 square miles, or 1 3,000 square acres, willbe sufficient for upwards 

 of 16,000 years. But, deducting 1000 acres for that which has been already 

 wrought, and for whinstone-dikes, and such like in this field, we shall have 

 12,000 acres still to break, which, according to the highest rate of demand 

 that has hitherto taken place, will supply this district for 15,000 years, a pe- 

 riod much more than twice as long as that since man has yet existed. 



But, if we take into account the coal of the New Cumnock Basin, which, 

 though not hitherto accurately ascertained, seems to be much more extensive 

 than that of the Sanquhar, the treasure of fuel which this district of Niths- 

 dale possesses, appears almost unlimited, according to the present rate of de- 

 mand. 



• A fine collection of these has been made by the company at Wanlockhead, 

 and may be seen on application to the overseers. 



