1895. ] NEW YORK ACADEMY OF SCIENCES. 199 
parts they are unchanged. They are evidently earlier than the 
spherulites, for they show a general direction following that of 
the flow lines, without regard to the spherulitic structure. 
Microspherulites, showing the revolving cross under crossed 
nicols have been observed in a red felsite from Hanford Brook, 
collected by G. F. Matthew. Nodular felsites,in which the 
radial structure is not seen, occur in several places. This struc- 
ture in English rocks is believed by some authorities to be gen- 
rally secondary, arising from a progressive alteration of the rock 
proceeding from a central vesicle or some point of weakness, 
From the traces of radial structure preserved, it seems probable 
that, in some instances at least, the nodules in New Brunswick 
felsites are altered spherulites of large size. At Shanklin, near 
: 
i 
ii 
: 
min 
il 
mg 
UT 
f 
MH 
Mh 
Hl 
i 
i 
h 
i 
Mt 
‘ 
i 
fy 
2 
1 
ON 
‘ 
Lf 
i 
va 
Fig. A. Trichites in spherulitic felsite. Spec. 664. _Magni- 
jied 153 diameters. 
Quaco, is a bright red nodular felsite forming an outlier in Sub- 
carboniferous shale. It is lithologically like the volcanic hills 
near by, and probably of the same age. The nodules in this 
rock are strongly marked in the weathered specimens, from the 
abundance of hematite in their outer zones; they often fall out 
of the matrix on slight weathering, being apparently more silici 
fied and better able to resist alteration. They have usually a 
central filling of feldspathic material free from iron; the iron 
has collected chiefly at their surfaces. In thin sections traces 
of a radial structure seems to be preserved in the arrangement 
of the secondary hematite flakes. The whole substance of the 
rock is much silicified, but both in the transparent centres and 
