
Obsidian possibly used in trephination experiments
1918-1920
1918-1920
1903
1901-1920
1903
1918
1900-1910
1952-3
1905
1830 (original); 1967 (model)
circa 1919
circa 1900
1919
1801-1840 (original); 1901 (model)
1900-1920
1911
1917
1902
1901-1910
1915-1918
1920
1914-1916
1909-1910
1913
circa 1900
1900-1920
circa 1915
1775-1799 (original); 1900-1907 (model)
1901-1920
1915-1918
1668; 1924
1610; 1923
1907
around 1900
1901
1904
1910
1915
1920
1915
1910
1908
1901
1918
1904
circa 1910
1914-1920
circa 1900
1909
1910
1922