72 The American Geologist. August, 1903, 
most of the little amphibole substance still remaining, there 
has occurred within the limits of the skeleton-crystals, the ex- 
tensive generation of chlorite, zoisite, calcite, chalcedony, and 
abundant, single and aggregated, grains of yellow epidote. 
The skeleton-crystals sometimes, though rarely, show a tend- 
ency to aggregate in either of two ways. They form small 
radial groups irregularly placed at intervals in the variole, or 
a number of the individual crystals may in the section, lie 
roughly parallel to one another in a manner very similar to 
that of the small, colored pyroxenes forming "palisade-struc- 
ture" in the varioles of the Annalong dike of Sollas. :;: The an- 
alogy between the Irish and Newfoundland varioles is so strik- 
ing that one is tempted to regard the skeleton-crystals of the 
American rock as pseudomorphs after pyroxene. Basal sec- 
tions have irregular octagonal outlines similar to those of phen- 
ocrystic augite. No trace of that mineral has heen found, 
however, and one can go with certainty no further hack in 
tracing the history of the skeletons than to the amphihole stage 
antedating the existing masses of secondary material. 
The ground-mass in which the skeleton-crystals are embed- 
ded, is a confused mesh of minute, relatively long, needles of 
tremolite or bleached actinolite, matted together with abundant 
chlorite, chalcedonic silica, epidote, zoisite, quartz, and, appar- 
ently, minute apatites. With the exception of the last-men- 
tioned mineral, of whose presence, indeed, the writer is not 
entirely certain, all this suhstance is plainly secondary. No 
trace of feldspar, or pyroxene and generally no iron-ore of any 
kind was to be discovered in the varioles. In one slide a couple 
of minute grains of magnetite probably represent primary ma- 
terial. There seems to be a relation between the size of the 
varioles and the length and thickness of the skeleton-crystals. 
The larger varioles so far as examined in thin section, contain 
the longest and broadest skeletons. 
Chemical analyses have not been made, since they could 
throw but little light on the original nature of the variolite. 
The character of the decomposition products, the relation of the 
varioles to the matrix, to the aphanitic crust and to the per- 
iphery of each pillow, are so closely similar to the variolite of 
* Proc. Roy. Dublin Soc, vol. vii, 1S92, p. 516. 
