100 —_ UM. EF. Wadsworth— Rocks of Newfoundland. 
: 
0. , from the central portion of the dike contains well- — ; 
developed biotite and augite crystals, with calcite and quartz 
grains. e the biotite crystals inclose portions of the . 
rock mass in the center. The section is composed of a dense — , 
Epo eer oe 
generally isotropic. The augites sometimes have greenish 
centers with yellowish external portions. One form, composed 
of veins of viriditic material inclosing dolomite, resembled an 
olivine pseudomorph. Considerable greenish fibrous spherulitie 
material, like delessite, occurs associated with calcite. a | 
No. 858 is from the center of the dike and is essentially the 
same as the preceding. : 
Of the ingredients of this dike, the augite and magnetite — 
alone of the minerals observed are regarded as original mate: — 
rials, all the rest'are considered to be secondary or alteration — 
products. : : 
No. 855 effervesces strongly with hydrochloric acid, but does — 
not gelatinize. 3 ae 
. res 
resembles the melaphyr, No. 865, previously deectibed: - 
preponderance of its original characters appears to be of al 
andesite type, and it is with doubt classed under that species. 
na similar manner from their structure and pseudomorphs, _ 
the minette (5015) from Himmelsfiirst, near Freiberg in Saxony, — 
and that from Weinheim in Baden (5080) appear to be altered — } 
and old andesites. a 
Porphyrite. o 
A brownish gray rock from Wells’s Cove, Exploits Bay, cuts 
the argillite and 1s composed of a brownish gray granulat — | 
groundmass with greenish spots, and segregations of calcite. — ) 
In the section it is seen to be composed of altered plagioclase — 
and orthoclase, with ferrite, quartz, calcite and chlorite forming — | 
groundmass which incloses larger, altered porphyritic feldspat — 
crystals. The plagioclastic forms appear to have predominat 
although the alteration is so great the decision is doubtful. 
n the present condition the mass is chiefly composed of second- 
ary ferrite granules, quartz, calcite and chlorite, with micro’ 
lites, etc, It is difficult to say to what species—basalt, ande- — 
site, or trachyte—this rock belonged, but it most closely 
resembles the andesites. ae 
a 
