I read all the way to the last comment, and nowhere did anyone mention the writings of a Spanish member of the conquest of the Inca who traveled down the Amazon to the Atlantic coast. He was quite impressed by the amount of civilization he found along the shores. No doubt he and his crew were generous in their distribution of new and deadly germs to the welcoming population which soon after ceased to exist.
Is it also possible that occasional volcanic eruptions sent burned waste and ash down the river which were collected and added to the shore soil?
I read all the way to the last comment, and nowhere did anyone mention the writings of a Spanish member of the conquest of the Inca who traveled down the Amazon to the Atlantic coast. He was quite impressed by the amount of civilization he found along the shores. No doubt he and his crew were generous in their distribution of new and deadly germs to the welcoming population which soon after ceased to exist.
Did a vehicle
Come from somewhere out there
Just to land in the Andes?
Was it round
And did it have
A motor
Or was it
Something
Different
Orellana’s account is a good suggestion. My guess is that tuberculosis and syphilis were the most deadly because of their long incubation periods. They would spread far and wide before people found out how sick they were.