He had also traveled further into the Ohio country than any previous expeditions.
It was smaller and lighter than his previous expedition, with only two other military officers.
Based on the previous expeditions, he estimated the total area of known wreckage at more than 20 square miles.
They also searched for the fifteen men left behind by the previous expedition, but found only bones.
The results of some previous expeditions will be disclosed this week in the journal Nature, due out tomorrow.
No records of previous expeditions or collecting trips have been discovered.
He had based his previous expedition in the same area.
It's one I brought back on a previous expedition and have been keeping here for additional work.
However, the situation had changed since his previous expeditions.
Powell believed they had killed the three men lost from his previous expedition.
