as held in place by ropes
passed over the house and weights resting on the roof. Sometimes to
the peak of a gable are fastened crosses, tiny flags, or the skulls of
animals--probably to avert the Evil Eye or bring good luck. Horseshoes
do not seem to be in demand. Horses' skulls, however, are deemed
very efficacious.

On the rim of the Titicaca Basin is La Raya. The watershed is so level
that it is almost impossible to say whether any particular raindrop
will eventually find itself in Lake Titicaca or in the Atlantic
Ocean. The water from a spring near the railroad station of Araranca
flows definitely to the north. This spring may be said to be one of the
sources of the Urubamba River, an important affluent of the Ucayali
and also of the Amazon, but I never have heard it referred to as
"the source of the Amazon" except by an adventurous lecturer, Captain
Blank, whose moving picture entertainment bore the alluring title,
"From the Source to the Mouth of the Amazon." As most of his pictures
of wild animals "in the jungle" looked as though they were taken in
the zooelogical gardens at Para, and the exciting tragedies of his canoe
trip were actually staged near a friendly hacienda at Santa Ana, less
than a week's journey from Cuzco, it is perhaps unnecessary to censure
him for giving this particular little spring such a pretentious title.

The Urubamba River is known by various names to the people who live on
its banks. The upper portion is sometimes spoken of as the Vilcanota,
a term which applies to a lake as well as to the snow-covered peaks
of the cordillera in this vicinity. The lower portion was called by
the Incas the Uilca or the Uilcamayu.

Near the water-parting of La Raya I noticed the remains of an
interesting wall which may have served centuries ago to divide the
Incas of Cuzco from the Collas or warlike tribes of the Titicaca
Basin. In places the wall has been kept in repair by the owners of
grazing lands, but most of it can be but dimly traced across the
valley and up the neighboring slopes to the cliffs of the Cordillera
Vilcanota. It was built of rough stones. Near the historic wall
are the ruins of ancient houses, possibly once occupied by an Inca
garrison. I observed no ashlars among the ruins nor any evidence of
careful masonry. It seems to me likely that it was a hastily thrown-up
fortification serving for a single military campaign, rather than any
permanent affair like the Roman wall of North Brita