In a Series of letters Escandon reports his advances in the colonization of the Seno Mexicano. He describes one by one the settlements that were founded, the number of families and soldiers that were left in each, the reaction of the Indians, etc. Due to the violent reaction of Indians and to previously unnoticed environmental disadvantages, not all the intended foundations are effected. New areas are explored and further foundations are suggested. All the letters are commented by the marques de Altamira (the auditor de guerra) who shows total support to Escandon and advises virrey to send reinforcements to the new villages for them to survive. (A. Nielsen, November 1989)