One mound held the shell literature

Claim (verbatim)

The nearest thing native North America kept to a codex archive was a single chamber: the Great Mortuary of the Craig Mound at Spiro, Oklahoma, where by the fifteenth century the Mississippian world had concentrated engraved whelk-shell cups and gorgets bearing its densest iconographic compositions — the Braden and Craig style corpora that anchor what scholarship calls the Southeastern Ceremonial Complex. In 1933-35 the Pocola Mining Company leased the mound and strip-mined the chamber for the relic market, dynamiting what remained as the lease expired: the continent's principal iconographic archive was dispersed in the space of one commercial season, and its contents are known chiefly through the corpus Philip Phillips and James Brown rebuilt from surviving pieces in the Peabody Museum's multipart Pre-Columbian Shell Engravings from the Craig Mound at Spiro (1978-1984). The structural conjecture: the engraved corpus was not free decoration but a constrained emblematic system — a notation short of script — and constraint is measurable as combinatorial grammar: a bounded motif inventory, heavy reuse, and positional syntax binding specific motifs to specific fields of the composition. Cahokia-scale coordination needed communication technology; the shell cups are the strongest surviving candidate for its ceremonial register, and the question is quantitative, not impressionistic. Prediction: a motif-combinatorics census over the Phillips-Brown corpus will find the twenty most frequent motifs covering over 60% of motif occurrences, with specified motifs bound to specified compositional fields in over 80% of their occurrences — grammar-like positional constraint distinguishable from free ornament — and over 80% of North America's known engraved whelk-shell cups tracing to this single deposit (primary clause: the positional-constraint census; the verdict follows it). Kill: not yet built — to be assembled from Phillips and Brown, Pre-Columbian Shell Engravings from the Craig Mound at Spiro (Peabody Museum, 1978-1984), James Brown's The Spiro Ceremonial Center (Michigan, 1996), and the Spiro holdings records of the Sam Noble Oklahoma Museum, the NMAI, and the Gilcrease Museum.

Prediction clause (verbatim)

Prediction: a motif-combinatorics census over the Phillips-Brown corpus will find the twenty most frequent motifs covering over 60% of motif occurrences, with specified motifs bound to specified compositional fields in over 80% of their occurrences — grammar-like positional constraint distinguishable from free ornament — and over 80% of North America's known engraved whelk-shell cups tracing to this single deposit (primary clause: the positional-constraint census; the verdict follows it).

Kill-dataset (verbatim)

Kill: not yet built — to be assembled from Phillips and Brown, Pre-Columbian Shell Engravings from the Craig Mound at Spiro (Peabody Museum, 1978-1984), James Brown's The Spiro Ceremonial Center (Michigan, 1996), and the Spiro holdings records of the Sam Noble Oklahoma Museum, the NMAI, and the Gilcrease Museum.

Novelty / leakage triage

anticipated in the literature — this exact test has never been run

Phillips and Brown catalogued and stylistically classified the Craig Mound engraved-shell corpus (Braden and Craig styles), Brown's monograph reconstructs the Great Mortuary and its dispersal by the Pocola Mining Company, and Spiro's dominance among engraved whelk-shell cups is broadly recognized. But the primary clause is an explicit combinatorial-grammar census — top-twenty motifs over 60% of occurrences, specified motifs bound to specified compositional fields in over 80% of cases — and the conjecture states this dataset is 'not yet built.' The motif-positional-syntax quantification distinguishing grammar-like constraint from free ornament is the un-run study; the corpus and its iconographic description are the worked neighborhood.

• Philip Phillips and James A. Brown, Pre-Columbian Shell Engravings from the Craig Mound at Spiro, Oklahoma (Cambridge, MA: Peabody Museum Press, Harvard University, 1978-1984)
• James A. Brown, The Spiro Ceremonial Center: The Archaeology of Arkansas Valley Caddoan Culture in Eastern Oklahoma (Ann Arbor: Memoirs of the Museum of Anthropology, University of Michigan, 1996)

Predictions

No prediction registered yet.