lakes frequently shown on maps of Cagayan Province, one east and one
west of the Rio Grande de Cagayan near the eighteenth parallel, are
not known to exist, though it is probable there is some foundation for
the Spaniards' belief in the existence of at least the eastern one. In
the bottom land of the Rio Grande de Cagayan, about six hours west
of Cabagan Nuevo, near the provincial border of Cagayan and Isabela,
there were a hundred acres of land covered with shallow water the last
of October, 1902, just at the end of the dry season of the Cagayan
Valley. The surface was well covered with rank, coarse grasses and
filled with aquatic plants, especially with lilies. Apparently the
waters were slowly receding, since the earth about the margins was
supporting the short, coarse grasses that tell of the gradual drying
out of soils once covered with water. In the mountains near Sagada,
Bontoc Province, there is a very small lake, and one or two others
have been reported at Bontoc; but the mountains must be said to be
practically lakeless.

Another mountain range of northern Luzon, of which practically no
details are known, is the Sierra Madre, extending nearly the full
length of the country close to the eastern coast. It seems to be an
unbroken, continuous range, and, as such, is the longest mountain
range in the Archipelago.

The fourth type of surface is the level areas. These areas lie mainly
along the river courses, and vary from a few rods in width to the
valley of the Rio Grande de Cagayan, which is often 50 miles in width,
and probably more. There are, besides these river valleys, varying
tracts of level plains which may most correctly be termed mountain
table-lands. The limited mountain valleys and table-lands are the
immediate home of the Igorot. The valleys are worn by the streams,