QO SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 66 
were first called to the attention of archeologists by Jackson and 
Holmes over 40 years ago, and are particularly abundant along the 
McElmo and its tributaries. The tower is not limited to this area, 
but is intimately associated with another widely distributed well- 
Fic. 96.—Pinnacle Ruin, McElmo Canyon, Colorado. 
Photograph by T. G. Lemmon. 
defined architectural type known as the circular ruin, which is most 
abundant in a narrow zone extending north and south, midway 
between eastern pueblos and the Hopi. There are important varia- 
tions in the form of towers in different areas, and it is instructive 
