... 'an, unearthed some brown pottery fragments, which led to the great discovery of the executed terra-cotta legions as an exterior section ... soldiers suggest that this was likely the headquarters of the troops of Vault 1 and 2.However, the commander is missing. Many ... alloy of copper, tin and various other elements, including nickel, magnesium, and cobalt. The arrow-heads which contain 7.71 percent ...