PLATE VI. 
THIN SECTIONS OF ROOFING SLATE WITH SLIT CLEAVAGE (" FALSE 
CLEAVAGE "). 
(A) Microscopic view of a thin section of purple Cambrian roofing slate from an old 
quarry three-fourths of a mile south of Fair Haven, Vt., showing slip or "false" 
cleavage originating in minute wrirfkles. Section transverse to both cleavages. 
Enlargement, 55 diameters. 
(B) Microscopic view of a thin section of green Cambrian roofing slate from the 
Huckleberry Hill quarry, 2 miles southeast of West Pawlet, Vt., showing slip 
or "false" cleavage. Section transverse to both cleavages. Enlargement, 55 
diameters. The black spots are pyrite. This figure represents a small part of 
the dark band shown in Fig. C. 
(C) Microscopic view of the same thin section, entire, showing alternation of fine 
and coarse beds, some of which are pyritiferous, and only in one of which is the 
false cleavage pronounced. Enlargement, 4 diameters. 
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