24'2 Messrs. Von Oeynhausen a?id Von Dechen 07i the 



and strings which contain tin ore, and in the neighbourhood 

 of which the granite also contains tin oi'e. These veins consist 

 chiefly of quartz and schorl, and have the strongest resemblance 

 to those which occur at Cligga Point; even their influence 

 on the rock through which they pass, is the same. The walls 

 of these veins at Carclaze are very hard, quartzose, of a grayish 

 hue, and not at all decomposed. These tin lodes run in every 

 direction through the granite, but they are more prevalent in 

 one direction than in any other, that is in a direction 22 de- 

 grees north of west ; their underlie is towards south, the angle 

 they form with the horizon being 35 degrees. The distances 

 between these veins being very short, they give to the rock 

 a stratified appearance. Other tin lodes run between 15 

 and 30 degrees east of north ; they intersect the former tin 

 lodes without heaving them, and also without being heaved 

 by them : it is said that very rich tin ores are found where 

 these different lodes intersect one another. These veins pre- 

 sent frequently in the interior an open string, or white quartz, 

 with tin ore and wolfram ; the walls are changed to a width 

 of a few inches only, so that their whole breadth does not 

 exceed from two to six inches; it is seldom twelve inches. 

 Besides these tin lodes, white quartz veins occur here run- 

 ning between 15 and 30 degrees west of north, being nearly 

 perpendicular; the quartz is crystallized from the walls to 

 the interior of the veins ; the breadth of these veins is from 

 one to two inches; they do not contain any metallic sub- 

 stance, and heave every tin lode they meet with in their 

 course. 



The granite in the southern wall of the excavation contains 

 a large portion of schorl at a depth of thirty or fifty feet under 

 grass; the quartz prevails more in these places than the fel- 

 spar, and the rock has not undergone so perfect a decomposi- 

 tion as in other parts ; this rock forms a transition to the schorl 

 rock, and is unquestionably the same rock that occurs before 

 you reach Cligga Point. The schorl occurs frequently in 

 granite, surrounding the opening of the mine near to the sur- 

 face. A tin lode called the black lode has been very produc- 

 tive in the parts where it crosses the granite, containing a large 

 portion of schorl. The lodes contain only tin ore and wol- 

 fram ; no copper or iron ore is found in them. This may be 

 considered also to be the principal reason why the tin ore in the 

 stream-work does not contain copper, taking its origin mostly 

 from granite countries. China-clay is raised on the north of 

 Carclaze, about one mile distant. The soil is covered there 

 by little quartz pyramids, as well as near Cligga Point, and 

 near St. Agnes' Beacon. The clay-pits are in a highly de- 

 composed 



