Mr Mentcath on the Geohgy of Nitlisdale. 317 



chief export from this basin. But, as the road communicating 

 with Dinnfriesshire to the eastward of Consonscon Hill is repair- 

 ed, and having a considerable descent all the way to Kirkcon- 

 nel, it is probable that the Mansfield coal situated in this basin 

 will be consumed in Nithsdale. This coal is very carbonaceous 

 and highly bituminous, with little or no pyrites. Its unsulphu- 

 rous nature renders it a most valuable article to the gas-maker, 

 maltster, lime-coke burner, smelter of ores, and to all who in- 

 dispensably require purity of fuel in their operations. It is at 

 present employed to prepare the gas for lighting the streets of 

 Dumfries, though at a distance of more than thirty miles; and 

 its coke is carried as far as Ayr. 



3. Basin of Sanquhar. — The riverNith, after leaving the Basin 

 of New Cumnock, crosses a grcywacke ridge through rather a 

 narrow ravine, and enters the Basin of Sanquhar. In this ridge 

 amygdaloid occurs. The hills which surround this basin are of 

 greywacke. They are loftier, and of more pleasing form than 

 those of New Cumnock. The Killa, the Youchan, the Crawick, 

 and the vMcnock, have their sources among them, and in their 

 course, before falling into the Nith, afford sweet pastoral 

 scenery. 



The secondary rocks in the Sanquhar Basin are the coaljbr^ 

 mation, and secondare/ trap. The coal Jbrmation occurs only on 

 the bottom of the basin. It stretches along both sides of the Nith 

 for about seven or eight miles, but scarcely exceeds two miles and 

 a-half in width. Its position is very irregular. The strata are 

 frequently broken, thrown down, and, as the collier expresses 

 it, are full of troubles. They are crossed by two dikes or veins 

 of secondary trap or greenstone^ which, in their course, alter 

 the position of the strata. Near to these dikes the coal is char- 

 red, and of inferior quality.* The coal of this basin has a splin- 

 ty character, is generally sulphureous, and leaves a great quan- 

 tity of slaty ash after combustion. Of the twelve beds, -f- ascer- 



• Professor Jameson remarks, that a little above Crawick Biitlge, there is 

 a bed, about four feet thick, of columnar glance-coai or graphite : it is traversed 

 by a vein of greenstone.— Mtn^o/o^ of Dumfriesshire^ p. 89. 



t According to the survey made by Mr Maclaren. 



