Careful analysis of architecture and archaeology of the America’s Stonehenge site has revealed that the site evolved through five distinct phases of usage and building over a minimum of a 2500 year period. Four of the phases involved the construction of various stone structures. These stone structures followed very specific architectural styles in vogue at the time of their construction. Towards the end of one phase and beginning of the next, a transition between architectural styles is seen. This allowed the phases to be placed in sequential order.
Phase 1 - Natural Features Era
This phase begins with the first ceremonial usage of the site which occurred prior to 3000 years ago. An exposed quartz crystal geode was found in the bedrock near the summit. The geode was at the base of six foot high ledge. Based upon later ceremonies which took place at the site, we know that Native Americans at some point observe during a storm, rain water flowing over the ledge, forming a waterfall, and then pooling with in the geode. This natural event had profound spiritually meaning for them. They ceremonially recreated this natural event by pouring water collected in a nearby wetlands pool over the ledge. The wetland pool being a source of rain water became a sacred feature of the site. A natural spring, now walled up into a well like structure was also the site of a ceremony. The earliest ceremonial usage of the site utilized existing natural features: wetlands pool, spring, and geode & ledge.
Phase 2 - Low Wall Era
This phase marks the beginning of man-made structures on the site. It is characterized by low walls which were used to construct enclosures, offering walls and walls with niches. In addition, several natural features were added: two caves at the cliff and a clay pit near the wetlands pool and spring.
Phase 3 - Tall Thick Wall Era
This phase was characterized by a use of tall thick walls. The first stone chambers were building during this phase. They were crawl height chambers. Tall thick walls were built extending above the chamber roofs forming a architectural facade. This architectural style served no obvious purposes in terms of construction technique or structural design. It purpose was symbolic and ceremonial. The style was derived from the characteristics of the small natural cave found on Mystery Hill.
Phase 4 - Walk-In [Height] Chamber Era
This phase was characterized by a major shift in architecture. The Native Americans developed roofed stone chamber of sufficient height for a person to walk into it. The collapsed chamber and the Oracle chamber were built during this phase. both chambers exhibited sophisticated design and multiple integrated features like windows and niches. Overall this phase saw the developed of complex elaborate ceremonial units and was arguable the pinnacle of construction and ceremonialism at the site.
Phase 5 - Slab Wall Era
This is the final building phase at the site. The chambers built during this phase used large stone slabs for their roofs and many of their walls. The structures and ceremonial units constructed in this phase exhibited a simplicity of design and construction which contrasted sharply with the elaborate ceremonialism and architecture of previous phase.