Obsidian possibly used in trephination experiments
1918-1920
1918-1920
1992-1999
circa 2016
1999-2001
1775-1785
1801-1900
1901-1930
1866-1870
1875
1701-1800
1999-2001
1790-1831
1901-1930
1998
circa 2016
1992-1999
1601-1700
circa 2016
1910-1937
1914-1918
1915-1953
1981-1990
circa 2016
1950
1601-1700
circa 2016
1851-1900
1740-1840
1890-1910
1701-1800
1701-1800
1701-1800
1901-1999
1980-1985
2015
1850-1910
circa 2016
1998
2016
1914-1918
1860-1910
1900-1915
2017
1970-1985
1871-1930
circa 2016
1998
1980-1990