1869.] MACFARLANE — GEOLOGY OF LAKE SUPERIOR. 459 



Finally I may remark, that I have found Mr. Bahr's interest- 

 ing statement that the rock contains iodine confirmed. When 

 7.5 grammes of substance, containing 21.7 p.c. of ash, were 

 burned with 14 grammes of almost pure lime, the burned mass 

 treated with water and nitric acid, and the iodine transf^rred to 

 Silver and thence to cadmium, the little amount of solution of 

 cadmium showed strong signs of the presence of iodine. The 

 iodine was recognized by receiving it first on chloroform, thence 

 on silver again, and lastly on starch. 



When twelve grammes of the same kind of lime were dissolved 

 with proper care in water and the same kind of nitric acid as 

 that used in the experiment, the solution, when analogously 

 treated, yielded a little chlorine but no trace of iodine. For the 

 sake of brevity I do not here detail any operations caused by the 

 substance's containing sulphur, especially as fuller details of the 

 experiments will shortly be published in the proceedings of the 

 Royal Swedish Academy. 



ON THE GEOLOGY AND SILVER ORE OF WOODS' 

 LOCATION, THUNDER CAPE, LAKE SUPERIOR. 



By Thomas MacFarlank. 

 Part II. 



{Continued from })a(je 47.) 



On the north-western part of the location a large area is 

 occupied by the rock which forms the summit of the clifis of 

 Thunder Cape. hX the western end of these cliffs, on the 

 location, this rock is found to overlie the grey argillaceous sand- 

 stones and shales, described in the first part of this paper. In 

 following the line of junction between these and the overlying 

 crystalline rock, the observer frequently fancies that he can detect 

 unconformability ; but so slight is the dip of the underlying 

 strata, and so inaccessible in places is the point of contact, that 

 it is impossible for him to obtain certainty until he reaches the 

 eastern end of the cliffs. Here, not only does the unconform- 

 ability become plainer, but the conglomerate bed and the white 



