After Anna had her pet turn around, and fly towards the rocky mountain, she expected the trip back home to be quick. It was a reasonable expectation, but as she flew towards the mountain, she got curious.
The bottom of the rocky mountain had a river passing through it, and this river headed east, towards the sea. She wanted to get a general idea of how straight this river was shaped, in terms of directions towards the sea.
If the river bed was as straight as an arrow, she may just need to follow it next time, straight to a salt deposit, instead of searching the entire shores of the sea for salt. Salt deposits had a better chance of forming where the river met with the sea. It should shorten their hunt for salt dramatically.
