350 Mr. Nixon on the Measiiremcnt {by Trigonomctrij) of the 



tainly not the coal itself, but the outburst of a bed of such ar- 

 gillaceous schist as invariably accompanies coal-beds, mixed 

 with a few small pieces of coal, probably proceeding from the 

 outburst or crop of a seam within a very short distance of the 

 spot. So strong indeed are the indications of coal at this place, 

 that of its existence in the immediate vicinity I have not the 

 slio-htest doubt. Of its qualities, thickness, &c., of course no 

 idea can be formed without boring; but there is every reason 

 to suppose that the same beds will be found here as those which 

 are at present sinking to at Whitwick and Ibstock. 



Note. — From the hasty manner in which this survey was made, I had no 

 opportunity of taking elevations ; but it is extremely probable that the out- 

 break of the coal-measures through the new red sandstone near Birstall is 

 connected with the elevation of the ground. Near Ashby also I observed the 

 like appearance under similar circumstances, where, although thelow grounds 

 ai'e occupied by the deposit of new red sandstone, yet on the top of a hill 

 a bed of siliceous sandstone, evidently belonging to the coal-measures, pro- 

 trudes itself to the surface, and is quarried for the purposes of building. 



F.F. 



LII. On the Measurement [by Trigonometry) of the Heights 

 of the principal Hills of Wensleydale, Yorkshire. By John 

 Nixon, Esq.* 



EARLY in June last I commenced the above undertaking, 

 and succeeded, notwithstanding the extremely unfavour- 

 able state of the weather, in completing the requisite measure- 

 ments by the middle of July. With a view to increase the 

 accuracy of the survey, the third or verification angles of some 

 of the principal triangles were, however, obtained in Septem- 

 ber, at Ingleborough and Whernside ; and in November, at 

 Shunnor Fell : yet so unsatisfactory, in consequence of the 

 continued haziness of the atmosphere, were the observations, 

 as to render it doubtful whether it would not have been pre- 

 ferable to have rejected them. 



In the selection of the hills, the transverse and lateral (or 

 boundary) ridges, of which Wensleydale entirely consists, were 

 surveyed ; and the principal passes (or extreme depressions of 

 the ridges) being ascertained, the loftiest point of ground com- 

 prehended between every two adjacent passes was carefully 

 determined and marked for measurement. At the head of the 

 dale, several of the transverse ridges, diverging with a gradual 

 descent from one common crest, terminate in lofty and stee}) 

 head-lands, or knabs. As no part of hills of this description 

 could with propriety be designated the summit, the measure- 

 ment of the height of any other point was not attempted. 

 * Communicated by the Author. 



On 



