Which of the following cultures built the Craig Mound by hand using layers of dirt carried in basketfuls?

The Craig Mound is part of the Spiro archaeological site in Oklahoma, built by the Spiro mound builders. They constructed the mound by carrying and piling layers of earth in baskets. The Norman and Harlan groups are not the builders associated with Craig Mound, and the Clovis cultures lived much earlier.

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