Help needed to ID this club

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This has been up in the attic for 30 years in my 'no idea what it is ' pile .. would appreciate any suggestions. It is made of wood with what seems to be thich hide binding woven around the 'neck' . The shaft is 18 inches long and the head 8 inches . There is a 'tunnel under the binding on the top of the head which loks as though it held a projecting piece .. possibly a narrow axe or adze head .. but cant be sure.