are the springs that furnished the supply
to the reservoirs. The exterior walls, which are of stone, have no
openings, and would have to be scaled or battered down before access
could be gained to the interior. The successive stories are set back,
one behind the other. The lower rooms are reached through trap-doors
from the first landing. The houses are three rooms deep, and open upon
the interior court."<16> He was much pleased with the manner in which
they had terraced off the bluff of the mesas into little garden patches,
irrigating them from the large reservoirs from the top.

There is one feature common to all the Pueblo tribes which is necessary
to refer to here, from its connection with the ruined structures further
north. In all of the inhabited pueblos there is a structure known as
an Estafa, some pueblos having several. They are usually circular, but
occasionally (as at Jemez) rectangular. They are generally subterranean,
or mostly so. They are great institutions among the Pueblos. "In these
subterranean temples the old men met in secret council, or assembled
in worship of their gods. Here are held dances, festivities, and social
intercourse."

Another common feature, represented in this cut, is the watch-tower. It
is either round, as in this case, or rectangular. It may be interesting
to recall in this connection the signal mounds of the Mound Builders.
They were not always in the immediate vicinity of other ruins. Neither
can we state that there was a system in their arrangement, one answering
to another at a distance, and yet it was noticed where the rains were
numerous that several were in view from one point.<17> In dimensions
these towers range from ten to fifteen feet in diameter, and from five
to fifteen feet in height, while the walls are from one to two feet
thick. They are in many cases connected with structures rectangular in
form.

Illustration of Watch Tower.-----------

We will now leave the inhabited pueblos and the ruins in their immediate
vicinity and, going to the north, explore a section of country that
shows every evidence of having sustained a considerable population some
time in the past. To understand this fact clearly, it will be necessary
to fix the location of the places named by means of the map. From time
to time confused reports of the wonders to be seen in the San Juan
section of Colorado had appeared in the East, but the first clear and
satisfactory account is contained