On the Trail in the Middle Plains Archaic

Figure One - A mixture of McKean Complex projectile point types from the
Middle Plains Archaic. John Bradford Branney Collection.  

 

All dates/ages in my article are uncalibrated radiocarbon years unless otherwise stated. For a date/age estimate in calendar years, add approximately 600 to 800 years.

I am not using the term "point" in my article to describe the artifact's functionality, but as shorthand for "hafted biface". 

For years, archaeologists have been searching for evidence of prehistoric man on the prairies of the High Plains during the period from around 7,000 to 4,500 years ago. During that time frame, evidence of humans is extremely rare. In 1948, Ernst Antevs coined the term Altithermal to represent this time-interval, a period of dramatic climate change resulting in a much hotter and drier environment on the High Plains. 

Archaeological evidence indicates that the Altithermal was perhaps the hottest and driest period of time since the last Ice Age. There is no modern-day analogy for the centuries-long droughts that occurred during the Altithermal. This inhospitable climate was hard on plants, animals, and humans. Prairie grasses withered, water tables lowered, and ponds and streams dried up. With less grass and water, bison herd populations dwindled and the beasts that did survive relocated to ‘greener pastures’ along the Rocky Mountain foothills and the major river systems to the east, such as the Missouri River tributaries. Humans followed the bison herds, abandoning most of the prairies along the High Plains. 

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When bison returned to the plains around 5,000 years ago, the Bison occidentalis species had evolved into Bison bison, the modern species of today. Humans followed the bison herds back onto the High Plains. One of the first groups of humans to return to the prairies was a group of prehistoric hunters and gatherers from what archaeologists named the Oxbow Complex. Archaeological and geological evidence from Oxbow Dam in Saskatchewan placed the Oxbow Complex in the Middle Archaic around 5,200 years ago. Archaeologists and collectors have found evidence of the Oxbow Complex in Saskatchewan, Alberta, Montana, the Dakotas, Wyoming, Nebraska, and northern Colorado. 

The most distinctive artifact from this complex is a side-notched dart/knife form with deep basal indentations and prominent ears (figure two). The concave basal edge separated basal corners or ears that extended downward and outward. Basal thinning was common and light grinding often occurred on the stem edges of most points. 

Figure Two - 2.5 inch long Oxbow dart point made from
Knife River Chalcedony and surface found on private land in
Campbell County, Wyoming. John Bradford Branney Collection. 

Around 4,900 years ago, a different style of projectile point started showing up on the High Plains. The archaeological complex associated with these different projectile points became known as the McKean Complex from evidence found at an archaeological site in Crook County in northeastern Wyoming. 

The McKean Site (48CK7) was originally recorded by the Missouri River Basin Survey of the Smithsonian Institution in 1951. Extensive excavations were conducted at the site in 1951 and 1952. Large quantities of lithic artifacts were recovered, predominantly from two cultural levels which are now designated Middle Plains Archaic. The investigators recovered over one hundred projectile points from these cultural levels.

Investigators at the McKean site found a wide variety of projectile point styles. The initial investigator at the site, Richard P. Wheeler, proposed 'splitting' the projectile point variations into three separate point types. He named three-point types at the McKean site that still survive in the literature today; McKean Lanceolate, Duncan, and Hanna. 

University of Wyoming anthropologist William Mulloy later investigated the McKean site and interpreted the different styles of points as variations along a common theme. Mulloy proposed 'lumping' all three-point types into one single point type called McKean. 

Today, some of us split the McKean Complex points into two separate projectile point types; McKean Lanceolate and McKean Shouldered. These Middle Archaic points either have shoulders or they don't. Personally, I do not see much benefit in differentiating between the Hanna and Duncan types. Some points fit well within Duncan or Hanna, but many McKean Shouldered points morphologically fall in between.      

There is another Middle Plains Archaic point type not found at the McKean site but later associated with McKean points called the Mallory point. I will discuss Mallory in my next article. 

Figure Three - McKean Lanceolate points from the author's collection. 

Middle Archaic flintknappers made the McKean Lanceolate point type with convex blade edges that were slightly narrower at the base than in the middle. The base of the McKean Lanceolate point was indented, sometimes so deeply indented that it appeared to be a notch. Stem edges were NOT ground. In outline, McKean Lanceolate points look like some of the earlier point types, but morphologically they could not be more different than each other. While a few McKean points show good workmanship, most were asymmetrical with random flaking patterns.   

  

Figure Four - McKean Shouldered points from the author's collection. 

These were previously broken down into two-point types;

Duncan and Hanna.  John Bradford Branney Collection, 

The Middle Archaic flintknappers made the McKean Shouldered point type (figure four) with triangular blades with straight to slightly convex edges and angular to sloping shoulders. The point type had straight to slightly expanding stems with a v-shaped notch in the base. The points varied from shallow, angular shoulders to expanding stems with rounded or lobed corners. Blade edge notches were broad and shallow. Stems were seldom ground.

Figure Five - McKean geographic distribution
from www.projectilepoints.net. 

  

What was the typical lifestyle in the Middle Plains Archaic? 

The Middle Plains Archaic was a different lifestyle than the previous Early Plains Archaic people who abandoned the prairies at the beginning of the Altithermal. The McKean Complex, representing the Middle Plains Archaic spread quickly across the High Plains. These Middle Plains Archaic hunters and gatherers brought with them a new adaptation model that relied more on the seasons of the year for subsistence activities. Grinding stones for processing wild plants increased in quantity and roasting pits, sometimes used for centuries, were developed and extensively used. Across the High Plains, the quantity of stone circles increased substantially in the Middle Plains Archaic. The people most likely used these stone circles to hold down the bases of their tipis or lodges, although the stone circles appeared to have other purposes as well. Although bison were still an important dietary component within the Middle Plains Archaic lifestyle, smaller mammals and reptiles were also important.

John Bradford Branney holds a geology degree from the University of Wyoming and an MBA from the University of Colorado. He held various positions in the energy industry during his thirty-four-year career before he took up writing full-time. John has published eleven books and many magazine articles on prehistoric America and life in general. John lives in the Colorado mountains with his wife, Theresa, three German Shepherds, and an ex-feral cat

His latest book, Beyond the Campfire, takes place on the Pleistocene high plains of North America.