For the last couple of days, weve been tracing the course of our river upstream from where it joins its cousin, the Papaloapan, near to the town of Cosamaloapan. Its not a pleasant place and the presence of more than half a dozen heavily armed state security policeman in the town square even at lunch time, indicated a lively nature and a dangerous place for gringos laden with expensive technology to be come nightfall. But in very different times, this is where our French naturalist originally departed from and subsequently spent 10 or 11 days we estimate, paddling upstream looking for the source.