emmons] INVESTIGATION OF METALLIFEROUS ORES. 23 
Economic Work on Metalliferous Deposits now in Progress. 
In enumerating the different pieces of work which have not yet 
readied the stage of completion, the order followed will be geo- 
graphic, taking each State and Territory, in which actual work has 
been done, in alphabetical order. 
APPALACHIAN REGION. 
Mining in the Appalachian region, except for iron and coal, has 
been conducted mainly in widely separated localities, and there are 
few concentrations of metallic deposits which form mining districts 
comparable to those in the West; hence hitherto no studies of special 
areas have been made. In the course of journeyings, however, obser- 
vations have been made in different parts of the region, especially by 
Mr. Weed, of the copper deposits, many of which have been reopened 
since the rise in the price of this metal. On later pages he gives an 
interesting summary of observations on various of these deposits, 
notably in New Jersey, along the contacts of the trap bodies which 
break through the Triassic rocks, in the interior of Maryland, and in 
the southern part of Virginia and North Carolina. Such observations 
will be continued from time to time as the conditions of Survey work 
admit. 
ARIZONA. 
The copper production of Arizona has in recent years assumed an 
economic importance rivaling that of the Lake Superior region and of 
Butte, Mont., which up to a comparatively recent date had together 
furnished more than two-thirds of the entire copper output of the 
country. Its principal mines had in consequence been developed to 
such an extent that their study promised to yield valuable data of vital 
importance in the theory of ore formation, especially in the line of 
secondary enrichment, a process which is particularly active in warm 
and arid climates. Since the commencement of the decade, therefore, 
considerable economic work has been done in this Territory, of whose 
geology up to this time but little was known. The following areas 
have been studied : 
Bradshaw quadrangle. — This area was geologically surveyed during 
the summer of 1901 and its economic resources studied, as far as their 
development permitted, by T. A. Jaggar, jr., and Charles Palache, 
instructors of geology at Harvard University. Under ordinary cir- 
cumstances it would have been more logical to have commenced work 
in this region on the Jerome quadrangle, which adjoins the Bradshaw 
on the northeast, but work in this area would have necessarily been 
incomplete because members of the Survey had been refused admis- 
sion to the most important copper mine of the region, the United 
Verde, by the owner of the mine, for reasons best known to himself. 
