activities continued even after the centre was abandoned. The Late to Terminal Classic period saw the most evidence of subterranean use, and many of the caves and rockshelters near Pacbitun were extensively modified over that span. The modifications include broken formations, formal architecture, and large buried caches. Materials from the caves dating to the Middle Preclassic and earlier, as well as those from the Postclassic through Colonial periods, are limited. Nevertheless, Pleistocene period giant sloth remains were found in Actun Lak Cave, and the continuation of Maya settlement at nearby Tipu through the Colonial period indicates that the caves in Pacbitun region hold potential for signs of use during these earlier and later times. Archaeological history First reported in the 1970s, Pacbitun was excavated extensively in the late 20th century by archaeologist Paul F. Healy (Trent University) and, in the early 21st century, by Terry G. Powis (Kennesaw State University). Based on these multi-year investigations, it is evident that the site was inhabited very early in Maya history, and flourished during the Late and Terminal Classic period (550-900 CE), before being abandoned. There is, so far, almost no evidence of an occupation before 900 BCE, nor a significant habitation after 900 CE, during the Postclassic period. Important contributors to the knowledge and publications about Pacbitun include (alphabetically): Jaime J. Awe, Cassandra R. Bill, Arianne Boileau, Melissa Campbell, Kong F. Cheong, James M. Conlon, Shannon Coyston, Pamela J.A. Downe, Kitty F. Emery, Paul F. Healy, Christophe G.B. Helmke, Hermann Helmuth, Bobbi Hohmann, Gyles Iannone, David L. Lentz, Terry G. Powis, Cal Ritchie, Catriona Robertson, Vanessa Rodens, Rhan-Ju Song, Jon Spenard, Norbert Stanchly, Kay S. Sunahara, Teresa B. Wagner, Drew Ward, Jennifer U. Weber, Christine D. White, Anne Wiesen, and Lori E. Wright. Preclassic period There are three recognized phases of the Preclassic period (900 BCE-300 CE) at Pacbitun. These are the Middle Preclassic, Late Preclassic, and Terminal Preclassic. The phases are demarcated and distinguished by variations in, mostly monochrome, ceramics, and dated by radiocarbon determinations. Middle preclassic (900-300 BCE) Pacbitun was first settled as a small, farming village, during the local Mai phase of the Middle Preclassic period. Evidence for occupation occurs in Plazas A, B, and C, including a tall, plastered, intact stepped platform located below what is Plaza A today. Discovered in 2013, the likely cruciform-shaped platform, possibly with stairs on all four sides, has been radiocarbon dated to