The bones were too important and too rare to subject to procedures that might produce an unreliable number.

A third issue involved which part of the bone was being dated.

Bone contains multiple types of organic and inorganic material.

The most reliable for radiocarbon dating is collagen — the protein that forms the structural scaffold of bone.

But extracting clean collagen from very old bone requires chemical processing that was beyond routine practice in the early 1960s.

Collagen degrades over time, and ancient bone may contain only a fraction of its original collagen content, mixed with diagenetic products — materials produced by the chemical alteration of the bone in the burial environment.

Separating what was originally there from what accumulated afterward requires methods that were developed later.