The Beagle leaves Maldonado on July 24, 1833, and arrives at the mouth of the Rio Negro on August 3. Although the Rio Negro is the largest river on this part of the coast, the landscape is barren and covered in small rocks. The history of this area is complicated, as evidenced by ruins of European establishments. One of Darwin’s guides tells him about a rebellion by Indigenous Chileans against European colonists that ended with the death of 39 of the rebels. Darwin’s journal frames this as a conflict between “Indians” and “Christians” and seems to consider the outcome a victory for the Spanish. He is nevertheless dismissive of Spanish settlements in general, noting that the Spanish colonies don’t expand and grow as efficiently as the English ones do.

Darwin’s home base for this section of the journal is a town called El Carmen or Patagones, which is built into the face of a sandstone cliff along the Rio Negro. Indigenous people live alongside Europeans in this town, although Darwin is not impressed by their way of life or behavior, calling them an entirely “immoral” people. Darwin stays here for nearly two weeks, exploring and collecting specimens.

Near Patagones, Darwin visits a giant salt lake and witnesses the means of salt production.