30 NEW YORK STATE MUSEUM 
The succession is scarcely comparable with that at Garbutt, the 
center of the mining industry in this part of the field, where the 
gypsum rock occurs in two beds, each from 5 to 8 feet thick, sepa- 
rated by a bed of limestone ranging from 6 to 12 feet in thickness. 
The principal development in the Oakfield district, Genesee 
county, was the construction of a new calcining plant by the United 
States Gypsum Co. The plant has five vertical kettles, a very im- 
portant addition to the manufacturing capacity of the company al- 
ready the largest in the State. 
On the extreme section of the gypsum belt, near Akron, . the 
American Gypsum Co. maintained its usual operations, but the 
Akron Gypsum Co. closed its mines and plaster works in the fall. 
The existence of gypsum to the west of Akron was reported to 
have been proved by test holes; the discovery has not been succeeded 
as yet by any developments. A hole put down in the foot wall of 
the seam at Akron to a depth of 70 feet failed to show any work- 
able deposit, though farther east, in Monroe county, two distinct 
beds are known to occur. 
IRON ORE 
Iron mining in the State resulted in about the same output last 
year as in 1911. There was a better inquiry for ore than the 
market showed during most of the year before, but prices were 
not correspondingly higher to furnish the necessary incentive to en- 
larged operations. No new mines entered upon the producing stage. 
Exploration and development work, however, continued active, 
specially in the Adirondack region, and brought to light substantial 
additions to the resources that eventually should be turned to ac- 
count. . 
The production of iron ore during the last two decades is given 
in the accompanying table. The figures are based on lump ore and 
concentrates of commercial grades, and not on the mine output. 
which, by reason of the large proportion that is subjected to mill 
treatment, is considerably larger. The figures for ten years previous 
to 1901 have been taken from the volumes of the Mineral Resources, 
and the others compiled from reports submitted by mining com- 
panies. 
