Prehistory (the time before written records) is represented by a range of archaeological sites (in terms of both the type of site and the timing of the human activities that created it) on Fort Irwin. The times of use represent one of the challenges for local archaeology—can we identify when specific cultural changes happened on Fort Irwin?
In identifying general patterns, all but the last of the periods or complexes listed below share the names of stone point forms used to tip hand-held spears or other hunting weapons. In addition to hand-held spears, some of the older point forms most likely reflect use on relatively light spears, called darts, which were thrown with a spearthrower. Smaller and later points are generally associated with use of the bow and arrow.
Clovis—in some parts of North America, points associated with Clovis are dated to more than 12,000 years ago. In the Fort Irwin area at that time, the landscape was dotted with large lakes and would have offered relatively plentiful large game such as deer, antelope, bighorn sheep, and potentially a variety of now-extinct animals such as mammoth. Waterfowl would also have been present.
Lake Mojave—starting about 10,000 years ago, prior to the drying of the lakes, prehistoric peoples in the Fort Irwin area emphasized fine-grained volcanic rocks in making points. This type of rock is more difficult to work in flintknapping (the process of making flaked stone tools by using other tools, such as hammerstones or antler tines, to break the rock in a controlled way) than other local materials, but the points made are less likely to break during use. Grinding stones—which can be used for processing small animals and pigments, but were often used to process plant foods—date to this period and later.
Pinto/Deadman Lake—the relationship of these two periods or complexes, which both date from about 9,000 to 5,000 years ago, is not clear. Deadman Lake seems to be mainly associated with higher elevations in the Twentynine Palms vicinity southeast of Fort Irwin. Do differences in the types of artifacts reflect different cultures, or different “toolkits” used by the same people?
An important trend for Pinto was that volcanic glass, called obsidian, became a more common material for making stone tools. Often used in modern flintknapping because it is relatively easy to shape into stone tools (with caution, since freshly broken edges are sharper than surgical steel), obsidian can be sourced to the areas where it was obtained. In addition, a range of artifacts indicate connections to California’s coast and the American Southwest at this time.
Gypsum—beginning by about 4,000 years ago, groups in the area of Fort Irwin were apparently making more use of non-volcanic local rock, including chert, for making stone tools such as points. With generally drier conditions, smaller animals such as rabbits and hares appear to have become more important as a food source.
Rose Spring (a place as well as a point type)—possibly by about 1,750 years ago, points are generally smaller, a change thought to reflect use of the bow and arrow. Grinding stones were in common use.
Late Prehistoric—by about 850 years ago, pottery (generally very fragmented) made an appearance in the general area. Most on Fort Irwin is plain, but a few decorated sherds suggest cultural ties with other areas, such as the Colorado River and the American Southwest.