Caption: A little on the geology and structure of Stonehenge: "Map of the central stone structure at Stonehenge as it survives today. Stone numbers are those conventionally used in the recent literature and following Flinders Petrie (1853--1942) in 1880.
Note that the term "Sarsen" used on the key refers to the hard silicified tertiary rock local to the chalkland of the Stonehenge region (i.e., Salisbury Plain). Sarsen is an exceptionally obdurate form of sandstone. The reference to sandstone on the key is to other non-sarsen material. The term bluestone conveniently, though somewhat controversially, describes a generic group of igneous rock exotic to Salisbury Plain. The major group of bluestones visible today are dolerite whose provenance is thought to be southwest Wales. A number of other igneous rocks are represented within the arrays." (Slightly edited.)
A little on the history of Stonehenge:
It is NOT clear when and how rapidly the Insular Celts arrived or arose from cultural transmission from mainland Europe in the Hiberno-British Isles. Probably after 1000 BCE. See Wikipedia: Insular Celts: Celtic settlement of Britain and Ireland for an inconclusive discussion.
It is the Insular Celts and at least some of rest of the Celts who had Druids---who did NOT build Stonehenge---and did NOT insofar has we know carry demonic rites there---despite what is suggested in Night of the Demon (1957 film).
You may well wonder how the Stonehengers transported the Sarsen stones. Modern experiments suggest that they slid the Sarsen stones on logs parallel to the direction of motion perhaps using animal fats (Wikipedia: Lubricant: History) as a lubricant. The Sarsen stones CANNOT have been rolled on logs: the logs just lock on each other. It probably took the Stonehengers a long time to move the Sarsen stones. They probably spent decades building the inner ring and the trilithons.
Credit/Permission: ©
Anthony Johnson,
2008
(uploaded to
Wikimedia Commons
by User:Sitehut,
2008) /
CC BY-SA 3.0.
Image link: Wikimedia Commons:
File:Stone Plan.jpg.
Local file: local link:
stonehenge_map_modern.html.
File: Stonehenge file:
stonehenge_map_modern.html.