Of all the ruins in Mesa Verde National Park only 28 have been named
and only 30 excavated. No survey of the unexcavated sites has been
made, and the total number of ruins is unknown. Several hundred cliff
dwellings have been discovered, and new ones will probably be found in
the more remote canyons. The surface pueblos outnumber the cliff
dwellings, and a careful search would reveal many that are now hidden
by a thick growth of underbrush. The earth lodges of the Late Basket
Makers are so common that hundreds will be brought to light by careful
search. Dozens of them can be located in a half-hour walk over any of
the mesas.
DATES FOR MESA VERDE RUINS ESTABLISHED
BY THE TREE-RING CHRONOLOGY[2]
Dr. A. E. Douglass, director of Steward Observatory, University of
Arizona, established the tree-ring chronology for dating Southwestern
ruins. This chronology is based upon the facts that solar changes
affect our weather and weather in turn the trees of the arid
Southwest, as else-where, and that such affects are recorded in the
variation of tree-ring growth during wet and dry years. Thus the
tree-ring record of living trees has been extended into the past by
arranging beams from historic pueblos in their proper sequence so that
the inner rings of one match the outer rings of its predecessor, and
in turn match the rings of the living trees. After completing the
series from living trees and pueblos, of known dates, the record has
been continued through the cross-sections of prehistoric beams of fir
and pine that were chopped with the stone axes. The continuation of
this chronology is only limited by the finding of earlier beams than
those used in the established chronology.
The National Geographic Society tree-ring expedition took, in all, 49
beam sections from ruins within Mesa Verde National Park. During 1932
and 1933 further tree-ring research was carried on in this area and
additional dates have been secured. Presuming that the year of cutting
the timber was the year of actual use in construction, the following
dates have been established for the major cliff dwellings:
Mug House, A. D. 1066 Long House, A. D. 1204-11
Cliff Palace, A. D. 1073-1273 Square Tower House, A. D. 1204-46
Oak Tree House, A. D. 1112-84 Spruce Tree House, A. D. 1230-74
Spring House, A. D. 1115 New Fire House, A. D. 1259
Hemenway House, A. D. 1171 Ruin No. 16, A. D. 1261
Balcony House, A. D. 1190-1272 Buzzard House, A. D. 1273
Since considerable tree-ring material from these ruins remains yet to
be examined, the dates given above are not final. On the basis of
present evidence, Cliff Palace, the largest and most complex cliff
house within the park, shows an occupancy of 200 years.
It is an interesting fact that all of the dates fall just short of the
beginning of the great drought, which the tree-ring chronology shows
commenced in 1276 and extended to 1299, a period of 24 years.