44 NEW YORK STATE MUSEUM 



length of 2500 feet and is opened by a tunnel 1400 feet at an aver- 

 age depth of 135 feet from the surface. The ore is not sharply 

 defined from the wall rock in most places, but shades over into 

 it through a gradual decrease in magnetite having the same non- 

 metallic constituents. The width to which the workings are carried 

 ranges from 50 or 60 feet to 100 feet or a little more. In its- gen- 

 eral features the ore body resembles some of the Adirondack de- 

 posits, and this resemblance is heightened by the fact that the im- 

 mediate walls as well as the gangue matter are constituted of syenitic 

 gneiss which has very similar characters to the syenitic ore-bearing 

 gneisses of the Adirondacks. 



Forest of Dean. This mine is in the Highlands of Orange 

 county and was active throughout the year except for a temporary 

 shutdown in the fall. Under the present management, that of the 

 Hudson Iron Co., who took over the property in 1905, the opera- 

 tions have been extended and the ore shipments increased until for 

 the last four years they have been at the highest rate in the his- 

 tory of the property. There is no apparent diminution in the size 

 of the ore body as the workings have been deepened, so that the 

 prospects for the future seem as good as at any time in the past. 

 The workings are 3000 feet long on the trend or pitch of the de- 

 posit and give an almost complete cross-section throughout the dis- 

 tance; few magnetite bodies are so well exposed for the study of 

 their physical features and underground geology. 



The Forest of Dean has had a long history. According to the 

 early records of Orange county, mining on the deposit began about 

 1756 and it was one of the sources of iron ore supply during the 

 Revolutionary War. It thus ranks with the Sterling mines, also in 

 Orange county, as among the oldest iron ore properties in the 

 county that are still in operation. In the early period of activity 

 production must have been small. Mather in his report on the 

 '' Geology of the First Geological District " of 1842 states that ex- 

 cavations had been made over a breadth of about 150 feet, which 

 from the context seems to mean that the body had been worked as 

 an open cut for- that distance along the strike. The output up to 

 that time is estimated by Mather to have been not less than 40,000 

 tons. From. 1865 to 1894 the mine was owned and operated by the 

 Forest of Dean Iron Ore Co., and the output in that period was 

 something over 500,000 tons. The production has acquired more 

 importance in the recent period of operations. 



