Beringia

Poul Anderson, The Shield Of Time (New York, 1991).

Contents of Book Four, "Beringia"

13,212 B. C. I-II
   1965 A. D.
13,212 B. C.
   1990 A. D.
13,211 B. C. I-XV
13,210 B. C.
   1990 A. D.

Wanda Tamberly:

studies Beringian paleontology BC;
confers with Ralph Corwin in 1965, the year of her birth;
confers with Manson Everard twice in 1990.

Thus:

a back seat for Everard;
prehistory instead of history;
20th century time has advanced from 1988 to 1990 and that is as far as it goes for the rest of the series, ten years short of the end of the 1850-2000 milieu.