CHARACTERISTICS, USES AND AGE OF CACHE PITS IN THE LOWER GRAND RIVER VALLEY, SOUTHWESTERN MICHIGAN

Archaeological investigations on a low terrace of the Grand River in southwestern Michigan revealed a number of shallow surface depressions, which upon excavation were identified as cache pits, i.e., subterranean storage features. The site would have been strategically ideal for overwinter storage of foodstuffs, due to its location near the river, and on well-drained, fine-sandy soils. Recent considerations of cache pit sites have focused on their role in broader adaptive strategies, but these discussions have been based on limited numbers of samples. In this paper we provide characterization and age data for a comparatively large sample of these pits, and set them within their cultural context. The site was excavated in 2011 as part of a larger investigation sponsored by the Michigan Department of Transportation, prior to construction of the US-31/M-231 Holland-to-Grand Haven highway bypass. Food processing and cache pits are widespread at the site, indicating that the area was frequently revisited for resource extraction, processing, and storage. Excavations of 29 cache pits revealed that they had all been backfilled with generally artifact-poor sands, native to the site. Prior to backfilling, the internal, wood structural materials and bark linings had been burned, leaving behind a black, charcoal-rich, charred horizon, marking the former base of the pit. This type of charred basal horizon is not usually observed in cache pits. Most of the cache pits are associated with small surface depressions, probably due to compaction of infilled materials. Subsequent pedogenesis below these surface depressions has formed tongue-like soil horizons in the infilled sediment, due to focused percolation. Radiocarbon dates on wood/charcoal from six cache pits, as well as diagnostic artifacts, indicate that most of these features date to the Late Prehistoric period, particularly the 15^th to mid-17^th centuries, although smaller, earlier components are also present. Although the use of subsurface storage features has a long history in the Great Lakes region, it became particularly important after A.D. ≈1200; data from our site provide one of the few detailed analyses of the morphology, taphonomy, and function of these features.