PALEO-INDIAN ERA
ca. 11,000-7500 BCE (Before Common Era = BC)
(left to right) Dr. Emil W. Haury (ASM Director and Head of UA Dept. of Anthropology) with Fred Navarrete (the man who discovered the site), Dr. John Lance (paleontologist with UA Dept. of Geosciences), and J. Cameron Greenleaf (UA archaeologist), at the Naco mammoth kill site, April 14-18, 1952. Clovis projectile points found in the rib cage of a 12,000-year-old Columbian mammoth at this ancient kill site provided the first substantial evidence of Paleo-Indian peoples in this region at the close of the last ice age.
An artist's conception of a Paleo-Indian mammoth hunt. Public domain.
The timing of the initial peopling of the New World is debated among archaeologists; some scholars argue that the first migrations took place as early as 15,000 years ago.
In Arizona, the earliest clear evidence of human presence, in the form of hunting sites associated with the Clovis Culture, dates to around 13,000 years ago, during the late phase of the Pleistocene era (the last Ice Age, 1.7M to 10,000 years ago). Archaeologists refer to this era as the Paleo-Indian Period. In southern Arizona, the Paleo-Indian period dates to ca. 11,000-7500 BCE (BCE (Before Common Era)=BC).
Clovis Points
A-32640
At that time, the southern Arizona landscape was not a desert but a land of grassy slopes and tree-covered mountains. Rainfall was much greater during the Pleistocene—about 40 inches a year instead of the current 12. Greater rainfall meant a lush environment with oak, hickory, and other trees growing along permanent water courses and bogs with dense plant stands that attracted a variety of animal species, many of which are now extinct.
These nomadic populations hunted herds of animals for their food, clothing, and tool materials, large mammals such as the Columbian Mammoth, Bison, and Great Ground Sloth. Several locales where these animals were killed and butchered by early hunters have been identified in southern Arizona, particularly in the San Pedro River valley.
A distinctive style of spear point known as a Clovis Point and other stone tools used for butchering are typically associated with these “kill sites.” Among the best known of these kill sites are the Naco and Lehner Sites in the San Pedro River valley near the modern border with Mexico. Two ranchers discovered mammoth remains at Naco in 1952 and alerted archaeologists, whose excavations uncovered eight points, some embedded and others mixed among the butchered mammoth bones. The Lehner Site, located on the west side of the San Pedro River valley along Mammoth Kill Creek, showed evidence of repeated hunting episodes and a campsite where the hunters probably processed and cooked the meat. The remains of nine mammoths and horse, bison, and tapir were present in the area. Similar kill sites have not been found in the Santa Cruz River valley, although several isolated spear points have been recovered. WATCH THIS RELATED VIDEO.
Dr. Emil Haury, then ASM Director and Head of the UA Dept. of Anthropology, articulating a mammoth rib cage with 5 embedded Clovis points. Naco Site, 1952.
Archaic Period
ca. 7500-2100 BCE (Before Common Era = BC)
Projectile points representing several different types that were prevalent during the Middle Archaic and Early Agricultural Periods. Bottom row: two Cortaro Style points, four Pinto Basin points, a Cienega Point, and a Jay point. Middle row: variations of San Pedro points associated with the Early Agricultural Period. Top row: a possible San Pedro point and two Basketmaker side notched points.
Basin metate with a one-hand mano made from a river cobble. This style of grinding stones, while able to grind corn, where more often associated with grinding hard shelled seeds and nuts.
As the environment became drier at the end of the Pleistocene, bands of hunter-gathers began to hunt smaller game such as deer and rabbit, and increasingly relied on plant resources such as mesquite and cactus fruits. These changes are marked by the use of smaller styles of projectile points , and an increasing number of grinding stones for crushing and milling seeds and pods. Archaeologists call this era of nomadic hunting and gathering the Archaic Period.