BAMiriCATIO^' OE TIIE MOIISTA.1S3. 
305 
this tract in so eastern a longitude (probably long. 74P), is 
the more remarkable, as ve find at four degrees ol latitude 
further north, neither a rock nor a hill on^the east of 
Xeberos, or the mouth of the Huallaga (long. / 7 5G ). 
We hare just seen that the spur of Beni, a sort of lateral 
branch, loses itself about lat. 8° ; the chain between^the 
Ucayali and the Huallaga terminates at the parallel of 7°, in 
joining, on the "west ot Lamas, the chain of Chachapayas, 
stretching betwen the Huallaga and the Amazon. Uinally, 
the latter chain, to which I liavc given the designation of 
‘ central,’ after forming the rapids and _ cataracts of the 
Amazon, between Tomependa and San Borja, turns to north- 
north-west, and joins the western chain, that of Caxamarca, 
or the Hevados of Pelagatos and Huaylillas, and forms the 
great knot of the mountains of Loxa. The mean height of 
this knot is only from 1000 to 1200 toises : its mild climate 
renders it peculiarly favourable to the growth of the cin- 
chona trees, the finest kinds of which are found in the 
celebrated forest of Casanurna and Uritusinga, between the 
Bio Zamora and the Cachiyacu, and between Tavacona and 
Guancabamba. Before the cinchona of Popayan and banta 
Fe de Bogota (nor. lat. 21“ to 5“), of Huacarachuco, Huam- 
alies, and Huanuco (south lat. 9“ to 11°), became known, the 
group of the mountains of Loxa had for ages been regarded 
as the sole region whence the febrifuge bark ot cinchona 
could be obtained. This group occupies the vast territory^ 
between Guancabainba,Avavaca,Ona, and the ruined towns ot 
Zamora and Loyola, between lat. 5^° and 3^°. Some of the 
summits (the Paramos of Alpacliaca, Saraguru, Savanilla, 
Grueringa, Cliulucanas, Giianiaiii, and Yamoca, which 1 
measured), rise from 1580 to 1720 toises, but are not 6\en 
Sporadically covered with snow, which in this latitude falls 
only above 1860 to 1900 toises of absolute height. East- 
ward, in the direction of the Kio Santiago and the Eio de 
Chamaya, two tributary streams of the Amazon, the moun- 
tains lower rapidly: between San Felipe, Jfatara, and Jaen 
de Bracamoros, they are not more than 500 or 300 toises. 
As we advance from the mica-slate mountain of Loxa 
towards the north, between the Paramos of Alpacliaca and 
Sara (in latitude 3“ 15'), the knot of mountains ramifies 
into two branches, which comprehend the longitudinal 
TOL. III. ^ 
