ALTERATION OF THE IVATEIl-T.EYEL. 297 
the eastern bank, the Sanariapo, and on the western, the 
'-ameji and the Toparo. Opposite the village of Maypures, 
the mountains fall back in an arch, and, like a rocky coast, 
form a gulf open to the south-east. The irruption of the 
river is effected between the mouths of the Toparo and the 
Sanariapo, at the western extremity of this majestic amphi 
theatre. 
The waters of the Orinoco now roll at the foot of the 
eastern c h a i n of the mountains, and have receded from the 
"'est, where, in a deep valley, the ancient shore is easily 
recognized. A savannah, scarcely raised thirty feet above 
the mean level of the river, extends from this valley as far 
as the cataracts. There the small church of Maypures has 
peen constructed. It is built of trunks of palm-trees, and 
ls surrounded by seven or eight huts. The dry valley, which 
runs in a straight line from south to north, from the Cameji 
to the Toparo, is filled with granitic and solitary mounds, 
all resembling those found in the shape of islands and shoals 
ru the present bed of the river. I was struck with this 
analogy of form, on comparing the rocks of Keri and Oco, 
situated in the deserted bed of the river, west of Maypures, 
Jfith the islets of Ouivitari and Caminitamini, which rise 
hke old castles amid the cataracts to the east of the mission, 
"he geological aspect of these scenes, the insular form of 
rile elevations farthest from the present shore of the Orinoco, 
“he cavities which the waves appear to have hollowed in the 
rock Oco, and which are precisely on the same level (twenty- 
uve or thirty toises high) as the excavations perceived oppo- 
se to them in the isle of Ouivitari ; all these appearances 
Prove that the whole of this bay, now dry, was formerly 
covered by water. Those waters probably formed a lake, 
the northern dike preventing their running out : but, when 
“his dike was broken down, the savannah that surrounds 
the mission appeared at first like a very low island, bounded 
7 two arms of the same river. It may be supposed that 
the Orinoco continued for some time to fill the ravine, which 
shall call the valley of Keri, because it contains the rock 
P* that name; and that the waters retired wholly toward 
ho eastern chain, leaving dry the western arm of the river, 
