@G.L. McDorman, Well, first of all, it does not seem to be impossibly outside the capabilities of the Shadow Children, who "sing" and manipulate across Space-Time to make people forget.
("Hold your hands before you thus, not touching. Now think of your hands gone. That is what we shake.”) But I don't think that's necessary. But for me, establishing a timeline based on references to nonspecific explorers or settlers has been a dry hole (although I'm willing to have my mind changed). I'll explain... I do not believe the references to "explorers" and "pioneers/settlers" should be read to as being a stratified in time (as in "first came the explorers and then the settlers"). It is established that settlers come in multiple waves -- first the "French" living there when the English-speakers take over, and then later the English. "Explorer" and "Settler" can apply to activity occurring in parallel and even in the opposite order. Marsch's June 6 diary entry itself says "We have behaved like explorers today, marched all day." I *think* a "pioneer" is a farmer. An "explorer" is a military or academic who is tasked with a job of entering the remote regions. Assuming my timeline, there were undoubtedly settlements and houses when the English arrived. Marsch actually visits a house like that. Additionally, I do say the French were ON St Anne going back 180 years or so. It would be weird if there were no written accounts of those early arrivals. But the Annese have had access to those written records as well, and for quite a long time. Marsch's diary is an example of what happens when written accounts fall into the hands of an "abo". I don't have the Orb edition, but I think there are at least three references to explorers and none of them provide enough context to establish a timeline. Are these the ones you're thinking of? I'll recheck my editions tonight.
tFHoC "I told her about my experiments (I was stimulating unfertilized frogs’ eggs to a sexual development and then doubling the chromosomes by a chemical treatment so that a further asexual generation could be produced) and the dissections Mr Million was by then encouraging me to do, and while I talked, happened to drop some remark about how interesting it would be to perform a biopsy on one of the aborigines of Sainte Anne if any were still in existence, since the first explorers’ descriptions differed so widely and some pioneers there had claimed the abos could change their shapes. " VRT "Actually some of the earliest explorers farther south are supposed to have reported signal drumming on the standing trunks of hollow trees by the Annese; they are said to have used no drum-sticks, striking the trunk with the open hand as if it were a tom-tom, and like all primitives they would presumably have been communicating by imitating, with the sound of their blows, their own speech-“talking drums.”) "
VRT
"As for there being “many people,” it reminds me of the man who said what he saw was sometimes like a man and sometimes like old wood. The truth is, in fact, that the reports are very contradictory. Even in the interviews I have, it’s often difficult to believe that two subjects are talking about the same thing, and the reports of the early explorers-such of them as have survived-show even less agreement. Certainly some of the more fantastic must be pure myth, but there remain a great many reports of a native race so similar to human beings that they might almost have been the descendants of an earlier wave of colonization."