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"Creation of The Spiro Mound"
By Larry and Christopher Merriam
Illustrations by Patrick Foster

First Published in, “Prehistoric American” Volume XXXVII Number 3, 2003

The Spiro Mound was part of the greater Spiro Mounds site located in Eastern Oklahoma on the south bank of the Arkansas River. The site occupied an area of 80 acres on an old high terrace overlooking the flood plain of the river. From the mounds you can see the buildings of south Fort Smith, Arkansas, some ten miles east. Five miles to the west is the small town of Spiro, Oklahoma. The most distinctive feature of the site was the saddle-shaped mound known as The Spiro Mound or the Great Temple Mound. (It has been renamed the Craig Mound, but the old historic Spiro Mound name will be used in this article.)

This mound was located on the east side of the site on the edge of the terrace overlooking a slough that was an old channel of the Arkansas River and probably served as the source of the dirt used to build the mound. To the south of this mound were the two small Ward mounds. To the west of The Spiro Mound and on the same elevation was a habitation area that was used during the earlier phases of the history of the site. Further to the west, on an elevated area, was a complex of 8 mounds surrounding a Plaza. The large Brown platform mound and the smaller Copple platform mound were the most distinctive features of this westernmost area.

Spiro was a ceremonial center and mortuary location. The complex was in use from approximately 950 A.D. until 1450 A.D. The Brown mound and the Plaza were the location of the ceremonial activities, at least for the first phases of the site’s life. The ceremonies were connected with the celebration of the lives of the dead elite and their ultimate interment in The Spiro Mound mortuary area. In the later stages of its life, the site became a vacant ceremonial center with few or no permanent living facilities. It should be noted that the Spiro people did not depend on agriculture and that maize was a minor part of their diet.

The Spiro Mounds group was the focal point of the Northern Caddoan Culture in the Upper Arkansas River drainage area. It was an extension of the Southern Ceremonial Complex which covered the entire southeast portion of the United States, from the Atlantic and Gulf Coasts to as far north as Cahokia. Spiro was the center of the western outpost of this cultural manifestation.

There were a couple dozen related sites within five miles of Spiro, mostly located on the south side of the Arkansas River. Other associated Spiroan sites were located mainly upstream along the Arkansas River drainage basin, up to 100 miles from Spiro. These extended west to the Groseclose site at Lake Eufaula, north to the Ozark highlands, and south to the Fourche Maline valley. There were no major sites of this cultural period in the Arkansas River valley east of the Spiroan area until you reach the unaffiliated Carden Bottoms near Dardanelle, Arkansas.

The Spiro Mound (Craig Mound) ran northwest to southeast for a distance of 350 feet along the edge of the terrace. It was composed of four co-joined cones, separated by “saddles” between the mounds, which gave it its unusual profile. The northernmost cone, which contained the Great Mortuary, rose 33 feet above the ground level and was 115 feet in diameter. The lesser cones were estimated from photos taken around 1913-1914 to be just over twenty feet high and eighty feet wide. The fourth cone to the southeast was separated from the rest of the cones by a lower saddle. This final configuration was the culmination of 500 years of evolution. The remainder of this article will cover this evolution of The Spiro Mound. This history is based mainly on the authors’ interpretation of the work of Dr. James Brown (1996)

The Spiro site was probably visited numerous times throughout prehistory but it wasn’t until the Late Archaic Period that evidence of occupation shows up in the archaeological record. Permanent site occupation began around 950 A.D. when the location was covered with an occupation of permanent four-center-post dwellings and specialized structures. Along the edge of the lower terrace, next to the slough, were the beginnings of The Spiro Mound with a line of at least three small separated burial mounds. They followed the same northwest to southeast trend that The Spiro Mound would ultimately occupy.
The discussion of features of the mound will be based mainly on the terminology of Brown (1996). The location of these features will be referenced to the final configuration of the mound.


First, the North Primary Mound occupied the extreme northwest edge of the northernmost and largest cone of The Spiro Mound. The second mound, the Middle Primary Mound, was roughly under the second cone from the north, the first of the three lesser cones. Between the North and Middle Primary Mounds, the Pre-mound Cemetery occupied the central area under the large cone. To the southeast, in the vicinity of the third cone from the north, was the South Primary mound. These were the only mounds we can be sure were in existence during this time period. However, there was probably an initial feature of some sort under the location of the fourth and final cone, the Percy Brewer Mound.

To the west of the Spiro Mound, on the same level as the mound, was the occupation area with the dwellings mentioned earlier. Further west on the elevated terrace was the Plaza with the circle of mounds around it. The largest feature was at the location of the Brown Mound, which was the center for rituals and ceremonies honoring the dead before their interment in the burial mounds at the terrace edge to the east.

This initial phase of development took place over a period of time, with each of the mounds being created at slightly different overlapping time periods. The last to be created, the North Primary Mound capped this phase of development around 1100 A.D. Brown calls this period the Spiro I grave period, which falls within the Evans and early Harlan Cultural Phases.

The next period was the Spiro II grave period, 1100 A.D. to 1250 A.D., which corresponds to the Harlan Cultural Phase. During this time, there was limited activity at the North Primary Mound. The Pre-mound cemetery continued to be in use but migrated slightly east. The Middle Primary mound was pretty much destroyed by the creation of a new feature, a large crematory basin. This basin and an associated feature will be discussed in more detail below. The South Primary Mound was probably at its peak usage with many of the artifacts uncovered from this area dating to this time period. The fourth mound unit, the Percy Brewer Mound, was certainly in use during this time. By the end of Spiro II, the three surviving Primary mounds, the North, South and Percy Brewer, were probably closed by being covered with a hard layer of earth to seal the mounds. Although this marked the end of their most significant activity, they would continue to be used.

Elsewhere on the site, to the west on the elevated terrace, platform mounds were built at the Copple and Brown locations over the foundation of former specialized structures. Domestic buildings continued to be erected but at a lesser frequency as domestic occupation of the site was coming to an end.

The most significant changes to The Spiro Mound were the ones occurring around the Middle Primary Mound. The mound was almost totally destroyed and in its place a giant crematory basin was built. The basin was circular, 16 feet in diameter and sunken, with a rim rising 1.6 feet above the center of the basin (Brown, 1996:77). The basin held the ashy remains of four or five layers of matting and some cremated bones. This basin would provide the foundation for the second cone of The Spiro Mound. Immediately west of the crematory basin was a new platform burial mound, the Southwest Flank Unit, in direct association with the basin. It was at the same level as the basin and contains a cluster of graves from this time period. This mound was at the southwest edge of the large cone of The Spiro Mound. At the end of Spiro II, the most significant area of mortuary activity was near the locality of the large cone of The Spiro Mound.

This period was followed by the Spiro III period, or Norman Cultural Phase, which lasted from 1250 to 1350 A.D. During this time, the upper layers of the Brown platform mound to the west were completed and by the end of this period that area of the site ceased to be used. The occupation area was also abandoned and Spiro became a vacant ceremonial center. All activities shifted to the east side of the site and The Spiro Mound itself.

The activity at The Spiro Mound became centered to the north in the area of the large cone. The large crematory basin and its associated Southwest Flank Unit were abandoned. The Southwest Flank Unit was replaced by a new rectangular feature to its north called the Central Flank Unit. Unlike the Southwest Flank Unit which had a concentration of burials within it, the new area was devoid of any Spiro III burials. This location, however, was surrounded by numerous graves. Assuming this rectangular area was used to store remains before burial, there was probably a mortuary structure located on top of a platform mound. There had been similar mounds structures located south of the Spiro Mound at the Ward Mound locations. These had been actively used during Spiro I and II but were being phased out during Spiro III.

The burials outlining the Central Flank Unit were concentrated to the south and east of it in the area that would become the Great Mortuary. The Pre-mound cemetery area continued in use to the east of the Great Mortuary. Burials were also occurring on the flank areas of the lesser mounds. There was a line of burials to the north called the Northeast Cluster that defined the northern edge of The Spiro Mound.

At this time, the three lesser cones were growing in height and diameter. Possibly, they had begun to overlap, forming a saddle-shaped group of three co-joined mounds.

The culmination of The Spiro Mound occurred during the Spiro IV period, from 1350 to 1450 A.D. This period encompassed the Spiro Cultural Phase and may have extended into the Fort Coffee Phase. The rest of the site was unchanged during this time, with only the Spiro Mound itself being active. This period would witness the dedication and construction of the large cone
at the north end of the mound unit. The basis for this development centered on the Great Mortuary.

The foundation for the Great Mortuary was what Brown (1996) calls the “central floor stratum”. It rested on a layer of bone and burial items from disinterred graves from other parts of the mound which had been covered with a layer of split cane over which a layer of dirt was placed. This floor encompassed an area 65 feet north-to-south and 40 feet east-to-west. On top of this layer were cedar pole litter burials, cane box burials, and extended burials. The litter and cane box burials were recycled skeletal remains and grave goods from other areas of The Spiro Mound. Brown (1996) feels this represents a bringing together of remains from prior generations of the elite leadership to inaugurate a new order and give it credence.

There were three rows of litter burials, consisting of sets of cedar poles at right angles to each other on which were placed many artifact pieces and some human bones, mainly skulls. Among the litters were the basket burials containing human remains covered with copper plates and other artifacts. The extended burials were placed at the semi-cardinal directions. These represented burials that were contemporary with the creation of the Great Mortuary. These extended burials had the greatest amount of grave wealth associated with them and represented the new elite leadership. They were placed on top of the old leadership burials in a superior position. There were additional baskets containing copper-headed axes, all sorts of beads, copper plates, and other caches of artifacts. There were piles of textiles covered with beads, marine shell cups full of shell beads, cedar human effigies, large human effigy pipes, a cache of stone maces and an extremely large number of engraved conch shells. It is this concentration of material wealth in one place that gives The Spiro Mound its reputation as the Great Temple Mound and assures its place in archaeological history.

But our story doesn’t end here. After the creation of the Great Mortuary, the offerings were sealed by a series of upright cedar poles spaced out in an irregular circular pattern leaning inward, like a teepee structure. The poles were roughly twelve feet long and did not come together at the top, leaving the center open. The sides of this structure were then packed with dirt and the Great Mortuary was rapidly covered. As the summit rose, a few new poles were placed above the buried ones in such a manner as to continue a series of overlapping poles to the summit. As a result of this construction, a hollow chamber was left behind, roughly fifteen to twenty feet in diameter and eight to ten feet high. It was this sealed chamber that preserved much of the unusual material which provides us with a more complete record of this culture.

Into the rising level of the large cone unit a large number of burials were placed into five or more level surfaces. There was a total lack of grave goods with those burials. The large cone was closed out with a hemispherical cap of earth. The level of the lesser cone also rose to new heights until the mound reached its final configuration around 1450 A.D.

After that, The Spiro Mound site was abandoned until its destruction began in 1933-1935 with the digging of the Pocola Mining Company. The Spiro Mound was ultimately leveled during excavations by the University of Oklahoma from 1936-1941. The mound was reconstructed in the 1970s and is currently the focal point of The Spiro Mounds State Park.

Reference: The Spiro Ceremonial Center: the Archaeology of Arkansas Valley Caddoan culture in Eastern Oklahoma by James A. Brown (University of Michigan, Memoirs of the Museum of Anthropology, Number 29, 1996)

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