of the Mines of Coniwall. 359 



the Cornwall Geological Society have kindly permitted me to 

 withdraw the before-mentioned paper, in order to its being 

 incorporated with the rest. When completed, I intend leaving 

 my work at the disposal of the noblemen and gentlemen whose 

 liberal assistance has mainly contributed to its completion. 

 But before I proceed, I am anxious to submit to your geolo- 

 gical readers a Programme of the manner in which I had 

 intended arranging the details, and I shall be exceedingly 

 obliged to any of them who will trouble themselves to point 

 out the defects, and to suggest improvements. Those who 

 are unacquainted with the interior of a mine will doubtless 

 notice in this outline many points of interest not described ; 

 the contact of veins at various depths, unseen ; and a general 

 scantiness of information. I may observe, that the excavations 

 are not always extended to the points at which interesting 

 phsenomena may be expected ; operations may have been 

 suspended, and the sides of the excavations either fallen to- 

 gether, been filled with water, or with foul air which ex- 

 tinguishes candles ; the vein may have been entirely worked 

 away, and in most cases the sides are after a short period 

 invested with a crust of ferruginous matter, which rapidly 

 accumulates. In a few instances I have not deemed it pru- 

 dent to expose myself to falling rubbish, on decayed wood, or 

 on rotten ladders. None but those who have experienced the 

 like can fully feel the many vexatious disappointments I have 

 had to suffer, in meeting an inmiovable barrier sometimes but 

 a few fathoms, or even a few feet, from my object; after having 

 crept hundreds of fathoms on all-four, and often on the belly, 

 through mud and water, often beneath tottering rocks. These 

 inconveniences, to which geologists who confine themselves to 

 the neighbourhood of the surface are not exposed, have been 

 every-day occurrences with me ; and I venture to hope that 

 they may with some propriety be offered as an apology for the 

 deficiencies which my outline will at every step present. 

 I remain, &c. 

 Perran Wharf, near Truro, Wm. J. Henwood. 



August 11, 1831. 



TROGRAMME. 



Cookskitchen Mine, j)arish of Illogan, near Redruth, is 

 situated on the northern side of the granitic range, of which 

 the nearest hill (Carnarthen Cairn) is only about half a mile 

 distant, and its acclivity is at an angle of about 7'^ The 

 phanomeiia of the interlying of granite and slate which here 

 occur have been often referred to, having for a considerable 

 time been supposed to be peculiar to this mine. The eastern 

 part of its suiface is nearly horizontal ; but towards the west 

 it rapidly declines. 



