An account of the specimens of hammered copper arrow-heads, tools, and ornamental objects made by prehistoric Indians which have been found in the fields, village sites, and burial mounds in the United States. Many thousands of such objects have been investigated; they show a somewhat sporadic industry, but considerable mechanical skill and artistic taste in their manufacture with stone and bone tools by the aborigines. The analysis of these hammered copper specimens indicates the source of the metal to be the native copper from the mines of Northern Michigan and not copper brought from Europe.