340 W. P. Blake—Columbite in the Black Hills. 
causes may have conspired in the destruction ;— 
climatic differences between the two sides of the continent, such 
had formerly recognized this element in our North Ameri- 
can flora; but I have only recently come to apprehend its full 
lands of the southwest. 
Gomera s Stee 
Art, XL.—Columbite in the Biack Hills of Dakota ; by 
Wm. P. Buakg. 
CoLUMBITE associated with cassiterite, albite and mica occurs: 
in several of the coarsely crystalline granite dikes which trav 
erse the mica schists and sandstones of Pennington County, 
E * 
A Si Se haa El I a cr ot th 
Seer Arlo oer eel ae 
