Mr. Nixon on the Trigonometrical Height of Ingleborough. 163 



often heard Mr. Sedgwick express his opinions to the same 

 effect. 



South of the Wharfe the main coal-seams again emerge, 

 and continue exposed throughout the great field of SouthYork- 

 shire and Derbyshire, as far as the banks of theDerwent; but 

 here they are again overlaid by the superincumbent strata, for 

 the red marl, sweeping round to the west in this direction, 

 overflows, as it were, all the extensive plains of our midland 

 counties, effectually concealing all the subjacent strata. 



I do not believe that any judicious endeavours have been 

 made to trace the probable prolongation of the coal-beds of 

 Nottingham beneath this covering to the south of the Der- 

 went ; and this is one of the points which most demands, and 

 would ultimately best repay, such researches. 



I am thus conducted to the scattered coal-fields of our mid- 

 land counties, which may probably be regarded as partial in- 

 dications of the southern extension of the fields already traced ; 

 but as these will require a more minute detail, I must reserve 

 them for a future communication. Your old correspondent, 



W. D. CoNYBEARE. 

 [To be continued.] 



B 



XXX. Trigonometrical Height of Ingleborough above the 

 Greeta at Ingleton. By John Nixon, Esq.* 

 AROMETRICAL observations of the altitude of Ingle- 

 borough above Ingleton, instituted with a view to improve 

 the formula of calculation, might be obtained under many ad- 

 vantages. Ingleton adjoins a great (coach) road, and possesses 

 more than one comfortable inn, situated within a short distance 

 of an eligible inferior station, more than 2000 feet below In- 

 gleborough. On the summit of the hill the substantial tower 

 lately erected would afford complete shelter to the observer, 

 and enable him to fix his barometer unexposed to sun, wind, 

 or wet. The descent is gradual, little obstructed by rocks or 

 bogs; and at one third of the distance to the village is a farm- 

 house, where the instruments might be left with perfect safety. 

 The indispensable datum of the trigonometrical height of the 

 mountain above some fixed standard at its base, I have at- 

 tempted to supply, and with, I trust, success, by the various 

 measurements of which the details are now given. 



At Ingleborough and at Hunt's Cross the angles for the 

 distances were measured by the 12-inch repeating circle de- 

 scribed in the Lond. and Edinb. Phil. Mag., vol. i. p. 340. 

 At the latter station, and also at the base line measured near 

 Ingleton church, the. vertical angles were obtained by the 

 horizon sector. 



• Communicated by the Author. 

 Y 2 



