12 GEOLOGICAL SURVEY OF ALABAMA 



which may be subject to material increase although still 

 inferior to similar Brazilian grades. The average annu- 

 al production for the period 1908 to 1913, was approxi- 

 mately 10 short tons, amounting in 1917 and 1918, to 

 about 2 per cent, of the world's production. Of this 

 production the United States received less than half, 

 most of the residue going to England. 



Peruvian production and exports have been thus far 

 so small as to be negligible. Shipments made mainly in 

 an experimental way from Guatemala, have not proven 

 generally satisfactory, the mica recovered being of green- 

 ish color, splitting badly, and proving after test unsuit- 

 able for electrical purposes. As the cost of production 

 is exceptionally high, owing to unfavorable mining con- 

 ditions in respect to occurrence, insufficient labor, and 

 defective transportation, no material increase in the re- 

 covery of mica of acceptable grade is at present probable 

 from the Guatemalan District, although recent exploita- 

 tion by surface workings only of new deposits in the De- 

 partment of Quiche, developed some mica of better grade 

 running to larger sizes. 



Production is Norway, confined to one locality near 

 Skutterud, on the southwestern coast, has been justified 

 during war conditions only, and is not likely to be con- 

 tinued, as the mica recovered has been mostly small and 

 of inferior quality. 



African production of sheet mica, although distributed 

 over an extremely wide area, is mainly confined as to 

 probable permanence and present importance, to former 

 German East Africa, where mica occurs in ten different 

 localities, the most valuable deposits being found in the 

 Uluguru mountains. The sheet mica recovered has been 

 of high grade, dark green or brown muscovite, unusually 

 clear and transparent, largely free from imperfections, 

 and occurring very frequently in large crystals. Limited 

 amounts of phologopite have also been recovered, but of 

 generally inferior quality and of small commercial value. 



The output of German East Africa, from 1908 to 1913, 

 averaged 127 short tons, constituting in 1913, 4.3 per 

 cent, of the world's production. During the war, this 

 production was materially increased advancing this Dis- 



