S6 Analyses of Books, [July ^ 



bcK^y with it at the meeting. The floor, therefore, probably 

 belongs to the same formation as the lode/' 



" Botallack is, however, the principal locality of the floors. 

 Here they have been discovered, first, m slate. There is only one 

 floor wholly in slate, which is 36 fathoms under the sea. It is 

 about a foot thick, and occupies the space between a side lode 

 and a neighbouring master lode, which is from 12 to 18 feet. 

 No junction of lodes takes place at this spot. They occur^ 

 secondly, between the slate and the granite. Here, in a part of 

 the mine called the Bunny, the principal floors have been found. 

 The highest floor was so shallow as to be level with the surface,, 

 and tradition reports it to have been discovered by some of the 

 tinstone having been kicked up by horses going over it : to this 

 succeeded a floor of the country from one to three feet thick :. 

 then followed a second floor of tin, under which was found 

 another floor of the country ; and in this manner no less than 

 seven floors of tin succeeded each other : the thickness of each 

 was from six to twelve feet ; some of them were full forty feet in 

 diameter, but in general they were not so large. The country 

 between the floors was generally slate, although they occurred 

 just at the junction of the slate and the granite. At this spot 

 there is a union of several lodes. It is singular that one of the 

 marks by which the miners knew they were approaching a floor 

 ©f tin, was their meeting with a floor of tourmaline, to use their 

 own expression, * the cockle rode on the tin.' Wherever they 

 discovered the tourmaline, they were confident of finding a floor 

 of tin under it. The tourmaline was accompanied by chalcedony^ 

 and I have seen veins of chalcedony running through it. 

 Thirdly, in granite. In another part of Botallack, there are no 

 less than 1 floors of tin, each as large as a space of about 30 

 feet square, succeeding each other in the same way as those 

 which have been already described. The first was very httle 

 below the surface : the last is about 36 fathoms deep : they are 

 from six to twelve feet thick. The agents of Botallack have 

 assured me, that although these floors appear to be connected 

 with one of the tin lodes, there is no junction of lodes in the- 

 space where they occur. In other parts of this mine, solitary 

 floors have been found at different depths, on one of which, at 

 22 fathoms under the surface, the miners are now at work. It 

 is about nine feet in diameter, and nearly round. They have 

 seen its extent, and have found the country both above and 

 below it (for it is quite horizontal) to consist of a very hard gra- 

 nite rock.'' 



"These floors have generally been regarded as the result of the 

 union of several lodes. This, however, is cutting a knot which 

 is not easy to untie. As some floors have been discovered 

 where no union of lodes has taken place, such a union does not 

 appear absolutely necessary to their formation. In the case of 

 a single floor of tin, not larger than those which have been 



