434 V. F. MARSTERS — ASBESTOS DEPOSITS OF BELVIDERE MOUNTAIN 



to indicate that a zone of fracture with marked shearing crosses the prop- 

 erty of the New England company. It is probable, too, that a smaller 

 one crosses the property of the National company. A third belt of frac- 

 ture with minimum shearing occurs on the property of Judge Tucker. 

 This case is adjacent to the igneous contact to be discussed in another 

 section. The fiber is largely of the " cross-fiber " type. It has the color 

 and luster of true chrysotile. Under the blowpipe it behaves in all 

 respects like the fibrous form of chrysotile. It yields considerable 

 water and is nearly infusible. There is a tendency on continuous appli- 

 cation of the flame for very fine films or strands of the fiber to become 

 noticeably brittle. The cross-fiber was, however, quite uniform in its 

 behavior before the blowpipe. Still one or two samples did not yield 

 as much water as should be expected in true chrysotile. How preva- 

 lent this may be has not been determined. 



The " slip-fiber " differs from the " cross-fiber " in having a duller and 

 waxy luster, less flexibility, and a tendency to develop a coarser but 

 longer strand, sometimes reaching 3 inches in length, while the latter 

 rarely attains 1 inch in length. Under blowpipe tests the slip-fiber 

 yields much less water and fuses, with some difficulty, to a white 

 enamel. The color test for calcium was also evident. These reactions 

 strongly suggest that the slip-fiber is not true chrysotile, but a fibrous 

 form of amphibole. This variety, however, is on the market as asbestos, 

 but its market values are much less and its uses not so great in range. 



Figure 3. — Cross-section of a Slip-block. 



Showing the minute fiber veins in a position where the block would be subjected to the greatest 

 strain, and hence offer the best lines along which the fiber might develop. 



At the lower contact of the serpentine with the amphibolite on the 

 Tucker property is the best showing of cross-fiber seen in the entire 

 belt. It is only just to say, however, that it does occur as well on the 

 land of the New England company, but in very small amount. While 

 cross-fiber is the more prominent of the two sorts, shearing, which seems 

 to be a constant associate with the slip-fiber, is by no means absent in 

 the Tucker exposures. It is confined, however, to very narrow zones. 

 On the other hand, the cross-fiber is very largely confined to the borders 

 of the thrust zone, and, so far as could be seen from the new exposures, 



