248 J. Orton on the Andes of Ecuador. 
30’. The true slope of the south side is 30° 45’; of the north, 
26° 45’; and of the west and east a little over 30°, Spruce 
gives 121° as the apical angle of the cone ; more correctly it 
is 122° 30’. On the summit is a circular parapet of scorie 
as on the Peak of Teneriffe. On the east side are signs of 
tween Cotopaxi and Iliniza, presents the following section 
showing the character and relative amount of material suc- 
cessively erupted : 
Soil, 1 ft. 
Fine yellow pumice, 5 
Compact black ashes with seams of pumice, 10% — 
Fine yellow pumice, 1 “ 6in 
Compact black ashes, ig 
Fine yellow pumice, 2° 
Compact black ashes with seams of pumice. 
Near Tacunga is the following section : 
Soil, 0 ft, 0 in 
Stones and cinders, i 
ine pumice, of 67 
Stones and cinders. 10 “ 
Compact black ashes, 
Compare a section at Pompeii : 
Soil, 
oe Brown incoherent tuff, 
- Small scoriz and white lapilli, 
| arthy tuff, 
The mud deposited at the foot of Cotopa 
n | q 0 * 
Pe n with oe blocks of dark trachyte, 
Square. They lie in rows: a 
are not the product of volcanic. eruption. 
| Otopaxi : 
rocks seen about C: 
E umice, — = of augi 
Porous trachyte, 
