These were not secrets or mysteries.

They were the practical knowledge of communities that had been sustaining children through northern winters for as long as the relevant histories extended.

Marie carried this knowledge.

She had grown up with it.

She had applied it during the Hunt overland expedition of 1811-1812, keeping her sons alive through a journey that was itself an endurance test.

She applied it again in the winter of 1814, under conditions that were worse.

The ability to keep small children functioning during a three-month winter survival journey in the Blue Mountains is not something that can be documented in the direct sources.