70 W. J. Henwood, Esq., on a 



Everywhere eastward the Wheal Laity lode is but a single vein 

 of about a foot and a half wide, and composed of quartz, earthy 

 brown iron-ore, greenish, and in some places brick-red, felspar, a 

 little tin-ore, together with some vitreous copper-ore, and iron 

 pyrites. Westward, however, it consists of at least two separate 

 veins, called, for distinction sake, the Wheal Laity north and south 

 lodes ; and sometimes there is also a third vein. At one spot the 

 third vein is simply crystallized felspar, and the axes of the crystals 

 are parallel to each other, but lie across the vein ; in other parts it 

 is slightly productive of tin-ore. The Wlieal Laity north, and 

 Wheal Laity south, lodes, in general from a foot to a foot and a 

 half in width, are occasionally much wider. Greenish felspar, quartz, 

 schorl, and occasionally brown iron-ore, are their chief ingredients : 

 in some parts both veins are rich in tin-ore ; vitreous copper-ore, 

 copper and iron pyrites also occur, but are not common constituents. 

 In the deepest part of the mine (i. e., at 150 fathoms deep), the 

 Wheal Laity north lode is for some fathoms in length about two feet 

 in width, and is then composed of chlorite, vitreous copper-ore, and 

 iron pyrites, and has a vein of rather fine-grained granite on one 

 side. At a depth of 120 fathoms, and about 60 fathoms west of 

 the portions already described, where the same lode consists of gra- 

 nite, quartz, red iron-ore, and a little tin-ore, there is connected with 

 its northern side {foot-wall) an off-shoot or excrescence, about four 

 fathoms in all directions, but most irregular in figure, and having 

 many small vein-like branches. This mass, consisting chiefly of 

 chlorite, quartz, and iron pyrites, is not only far richer in tin ore 

 than the adjoining portion of the lode, but is remarkably different 

 in mineral composition. We have thus the same ore richly im- 

 pregnating, not only the Wheal Comfort lode and the " Carbona," 

 two parallel but entirely dissimilar deposits, but also the Wheal Laity ■ 

 lode, which has a direction nearly at right angles to them. 



(c) The intersections of the lodes just mentioned exhibit almost 

 an epitome of that class of phenomena. 



(1) The Wheal Laity and the Wheal Comfort lodes cross each 

 other : still at some levels there is no evidence to show that either 

 is cut through ; whilst at others the Wheal Comfort lode not only 

 intersects, but also heaves the Wheal Laity lode. ^It is not the least 

 remarkable circumstance attending this intersection, that the Wheal 

 Laity lode is a single vein everywhere eastward of the Wheal Comfort 

 lode, whereas westward of their contact it is divided into two, and in 

 some places even into three distinct and separate veins. 



(2) All these veins are intersected by the Cross-course, and all 

 are heaved by it : the two larger (the Wheal Laity north and the 

 Wheal Laity south lodes) in general from 10 to 15 fathoms : the 

 displacement of the smaller vein is, however, much less considerable, 

 and does not exceed six fathoms and a half. 



Again, notwithstanding the Wheal Comfort lode and the Cross- 



