A strange turn of events in section 2 of The Professor's House

Willa Cather’s The Professor’s House (1925) takes a weird turn in section 2 (of 3), Outland’s Story, which is purpotedly a “memoir” that Professor St. Peter composes to capture some of the tales of youth that his favorite student and late son-in-law, Tom Outland, used to tell to entertain the St. Peter daughters (one of whom he will eventually marry). A # of things strike me as strange: Outland on the one hand seems much too old for this plot – he was an outstanding college student telling tales of his youth to the very young daughters of his favorite professor, and then w/in a few years marries the older daughter? He seems to be literally twice her age. On the other hand: he seems much too young for the part. He’s a college student (albeit he did not enter as a conventional undergraduate) and he has come from working on the railroads and in cattle ranching and has roughneck stories w/ which to entertain the St. Peter children: he seems here as if he must have been in his mid-20s when entering college. So I don’t know, maybe I’m messed up but either the chronology or the characterization seems off base. In this 2^nd section, Outland, via St. Peter, tells of a summer he spent grazing cattle in New Mexico w/ 2 other men, and of their explorations on what he calls the “blue mesa,” pretty much unexplored territory, on which he discovers ruins of cliff-dweller civilizations. I don’t know how much the world at large knew of the cliff dwellers in 1925 (or, the setting of this part of the novel, which was probably about 1910?), but maybe this is supposed to be the discover by white settlers of the Mesa Verde dwellings (though those are in SW Colorado)? Not sure the significance, to St. Peter or to this narrative, of this sudden shift in terrain and mode; I’m pretty sure we’re not heading toward a Broakback Mountain romance – but for some reason St. Peter feels compelled to preserve and to tell this tale – which must have some bearing on his family story and must be some foundation for Outland’s scientified success, which will lead to a great fortune for his widow (St. Peter’s daughter) and her “outsider” (that is, Jewish) businessman-husband.