412 MR. A. K, COOMARASWAMY ON THE [Aug. 1902, 
Sections prepared parallel to the plane of intergrowth yield a negative 
uniaxial interference-figure in convergent polarized light. in most 
cases the calcite and dolomite have an identical optical orientation, 
in others the alternating bands show a slightly differing orientation. 
Fig. 5.—Parallel intergrowth of calcite (dark) and dolomite. x20. 
[The shading represents the effect of staining with Lemberg’s solution. 
This applies also to fig. 6. TW=Twinning; CL=Cleavage. | 
Ramifying (graphic) intergrowths (fig. 6, p. 413).—On 
the weathered surfaces of other varieties of limestone, a vermicular 
tracery is often seen, frequently appearing to radiate from several 
centres. Fractured surfaces of such specimens present a ‘ lustre- 
mottled’ appearance. Thin sections show that these phenomena are 
due to ramifying intergrowths of calcite and dolomite. The radiating 
‘fingers’ consist of dolomite, with a common optical orientation; the 
calcite-individuals are numerous and variously oriented, but each is 
