VERMONT ASBESTOS 433 



modern machinery for the treatment of asbestos-bearing rock. Active 

 mining operations were begun in May, 1902, but in October of the same 

 year the plant closed its doors. No official statement has been obtained 

 concerning the amount or the grade of the fiber produced or its value 

 in the markets at that time. That seen by the writer, which was said 

 to have been the product of the New England mines, while too short for 

 purposes requiring tensile strength, should fill the standard require- 

 ments in the manufacture of all asbestos goods in which non-conductivity 

 of heat is the only essential quality desired. A view of the New England 

 plant is shown in plate 74. 



KINDS-SLIP-FIBER AND CROSS-FIBER 



While it is universally true that chrysotile is confined to serpentine, 

 it is by no means true that all serpentine deposits contain it. Although 

 the Belvidere area is a difficult one to investigate as regards struc- 

 tural details, sufficient data have been obtained to demonstrate with 

 reasonable certainty that the fiber contents are very largely restricted 

 to certain belts, the localization of which is due to structural feat- 

 ures confined to the serpentine deposits. In the open cuts and pros- 

 pects, made, especially by the New England Asbestos Mining and Mill- 

 ing Company and others near the upper contact with the amphibolite, 

 the fiber, when in sufficient quantity to be easily detected, shows 

 that it is largely confined to a shattered and sheared zone of rather 

 limited extent. In the central part of the zone are large masses with 

 slickensided surfaces. Wherever cross-sections of these could be found 

 careful examination revealed the fact that they in turn were also sheared, 

 and could with a little careful manipulation be separated into a series of 

 smaller wedge-shaped masses, each with smoothed surfaces. It is along 

 these planes that the fiber has attained its maximum development. It 

 occurs in two forms, and has been so recognized by the local prospectors. 

 In a large part of the zone of shearing the fiber has stretched or pulled 

 out along the slipping planes, and hence has been called "slip-fiber." 

 In certain parts of the area, however, there has been a maximum devel- 

 opment of fracture with minimum shearing. In such fractures the fiber 

 has assumed a transverse position, and is locally known as " cross-fiber." 

 The same phenomena may be seen in thin-sections prepared from smaller 

 blocks. 



With regard, therefore, to the structural details bearing on the areal 

 distribution of the fiber the facts as they now appear force the conclu- 

 sion that the fiber will be limited to the zones of fracture and shearing. 

 How many of these exist within the serpentine zone under consideration 

 is a difficult matter to determine. Enough data are available, however, 



