J. Orton on the Andes of Ecuador. 249 
Very compact trachyte, dark gray, (common.) 
Granular trachyte, whitish with hematite scales, * 
in ne-grained trachyte, dace mottled, * 
gr ay, “6 
= “« dark, very tough, ‘@ 
Porous trachyte, iron-stained, se 
Porphyroia oe black vitreous base, * 
olored, 
ie * fine grained, dark, i 
Obsidian, 
Fine-grained trachyte, dark, augitic, 
cell 
Soft, disintegrating i te, hardens under water, 
Feldspatho-augi itic : rock, re 
Coarse por phyroid tr achyte, reddish, 
gray, 
Tunguragua is a beautiful cone rivaling Cotopaxi; but it 
is 2,000 feet lower. Spruce calls one of the slopes 43° Li, and 
the apical angle 92° 30’. We found the west, east and ate 
slopes 38°, making an ee at the apex of 104°, The west 
side is covered with fine black sand; on the north is an im- 
Mense stream of black porphyroid frazments, much resembling 
the Antisana currents.* At the base of the mountain there 
lum 
oo prismatic form. At Bafios is a hot ealerys ing 
(130°), “The last eruption lasted from aid a 1780 ; but 
Spruce asserts sess he saw smoke ae set e western 
Vitreous wachyte, black with ns a feldspar crystals, (common.) 
Fine-grained trachyte, gray with anit — 
Porphyroid trachyte, banded black an nd 
da 
rk base, numerous ‘crystals, 
= “ dish “ 
5 4 gray, (rare.) 
: pater is the most alpine of the Ecuadorian mountains. 
_ ; fom the west it appears to be what it undoubtedly is, a bro- 
i volcano, poeaeiee eight snowy needle peaks sur- 
; ding an immense crater. = has not been active since the 
dag of the Incas ; but there is a tradition (still living in its 
Indian nam name, cappae-Urctl, the "chief ) that originally it over- ee 
