
Obsidian possibly used in trephination experiments
1918-1920
1918-1920
1934
1903
1901-1920
1903
1918
1935
1920-1925
1901-1930
1952-3
circa 1919
1905
1915-1925
1830 (original); 1967 (model)
1925-1935
1925-1935
1919
1928
1901-1930
1923
1801-1840 (original); 1901 (model)
1909-1932
1910-1923
1921-1931
1914-1916
1935
1911
1927
1917
1902
1936
1926
1901-1910
1920
1915-1918
1938
1909-1910
1901-1920
1927
1936
1913
1934
circa 1915
1915-1918
1668; 1924
1937
1930
1610; 1923
circa 1925
circa 1923