The Costello-King site (AZ AA:12:503) is the westward extension of the Las Capas site complex (Ezzo and Deaver 1998; Mabry 2008:27)--one of the largest and most densely occupied residential, mortuary, and agricultural sites dating to the Early Agricultural period in the Southwestern US. Costello-King is one of several Early Agricultural period residential sites along a 40 km long stretch of the Santa Cruz River valley in the Tucson Basin where archaeologists have recovered abundant maize in association with small oval semi-subterranean house pits and other features, including irrigation canals. Lisa Huckell (2006:100) notes that there are five AMS dated maize samples from this site, one of which was included in her morphological study of early maize from the Southwestern US: it was a 12-rowed cob (Huckell 2006:101). Ezzo and Deaver's dates (1998:23, Table 3) are reproduced in Mabry's (2008:64) compilation of maize radiocarbon dates from the Santa Cruz River Basin.
| ID | Other ID | Type | Subtype | Uncal BP (years) | ± 1 σ (years) | Median cal BP (years) | Lower cal BP (years) | Upper cal BP (years) | δ13C | Contaminated? |
|---|---|---|---|---|---|---|---|---|---|---|
| 106 | Beta-89860 | MacroSample | cob | 2770 | 60 | 2872 | 3058 | 2755 | -12.4 | No |
| 107 | Beta-89861 | MacroSample | cupule | 2770 | 60 | 2872 | 3058 | 2755 | -12.3 | No |
| 108 | Beta-89862 | MacroSample | cupule | 2690 | 60 | 2807 | 2944 | 2730 | -11.5 | No |
| 109 | Beta-89863 | MacroSample | cob | 2620 | 60 | 2746 | 2865 | 2493 | -11.3 | No |
| 35 | Beta-89859 | MacroSample | cupule | 2780 | 60 | 2884 | 3060 | 2760 | -11.5 | No |