AIM'IMUX 299 



Miners classify theif ore from its position in the mine. Ore 

 from Mfi and w st h ads, is raised from day diggings, although 

 these diggings may be punned under the first stratum of rock. 

 Ore from north and smith Ifodty is termed "sheet minerals," and 

 is usually taken from rock diggings. The vein or sheet stands 



perpendicularly in the fissure, and is usually struck in sinking 



from six ;o ten feet. The sheet varies in thickness from six or 

 eight inches, in the bromdesl part, to not more than one. The 

 great mass found at u Irish diggings*" was of this kind. 



I observed SfUOng the piles of ore at Gratiot's, the combination 

 of zinc with lead ore, which is denominated dry bon*. It is cast 

 by as unproductive. Mr. B. Gratk>1 also showed me pieces of 

 the common ore which had undergone desulphuration in the log 

 furnace. Its natural splendor is increased by this process, so as 

 to have the appearance of highly burnished steel. He also pre- 

 sented me some uniform masses of lead, recrystallized from a 

 metallic state, under the hearth of the asli furnace. The ten- 

 dency to rectangular structure in these delicate and fragile masses 

 is very remarkable. Crystallization appears to have taken place 

 under circumstances which opposed the production of a com- 

 plete and perfect cube or parallelogram, although there are innu- 

 merable rectangles of each geometric form. 



In the drive from Gratiot's to Willow Springs, we saw a suc- 

 cession of the same objects that had formed the prominent fea- 

 tures of the landscape from Galena The platte mounds, which 

 had appeared on our left all the morning, continued visible until 

 we entered the grave that embraces the site of the springs. 

 Little mounds of red earth frequently appeared above the grass, 

 to testify to the labors of miners along this part of the route. 

 In taking a hasty survey of some of the numerous excavations 

 of Irish diggings, I observed among the rubbish small llat masses 

 of a yellowish white amorphous mineral substance of great freight 

 I have not had time to submit it to any tests. It appears too 

 heavy and compact for the earthy yellow oxide of lead. I should 

 not be disappointed to find it an oxide of zinc. No rock stratum 

 protrudes from the ground in this part of the country. The con- 

 solidated masses thrown up from the diggings, appear to be sili- 



