greater al 
_ polarization 
M. FE. Wadsworth— Rocks of Newfoundland. 99 
tertiary basalts of California. In most of the fragments the 
fine basaltic feldspars retain their forms. 
These rocks belong to the old tufaceous products to which I 
have given the name of porodite,* but since the basaltic mate- 
rial predominates in them they are placed under that species. 
ANDESITE (?) 
Minette, or Mica Trap. 
brown color. 
_ The hornblende is in both short and elongated crystals, with a 
dichroism varying from light yellowish brown to dark brown. 
It is almost identical in general appearance with the mica, but 
1s optically different, while the cleavage of the hornblende is 
nearly wanting. Both minerals are abundant. The ground- 
mass is composed of a pale yellowish or grayish mass, mostly 
isotropic, but sometimes polarizing feebly; and ee 
numerous microlites, granules, etc. It also holds calcite an 
greenish fibrous spherulitic delessite (?), which sometimes forms e 
Concretionary masses with centers of calcite. 
ve g 
teration, the groundmass here shows generally some 
* 1. c. p. 280. 
