Sources

Poul Anderson's "Time Patrol":

derives its idea not only of a temporal vehicle but also more specifically of such a vehicle on which the time traveler sits as on a bicycle from HG Wells' The Time Machine;

derives the idea of a time traveler who deliberately sets out to change the history of civilization for the better from L Sprague de Camp's Lest Darkness Fall;

bases its idea of human beings evolving into Danellians on Darwinism, the same source on which Wells had based his idea of human devolution into Morlocks and Eloi;

derives its idea of a private inquiry agent who eliminates the impossible, then accepts whatever remains, however improbable, as the truth from Sherlock Holmes;

cites "...a tragedy at Addleton and the singular contents of an ancient British barrow..." (Time Patrol, p. 18) from the Holmes story, "The Adventure of the Golden Pince-Nez" (see here);

derives Rozher Schtein from 2987 with his thirtieth-century blast-ray from pulp sf.

Anderson successfully unites Wellsian sf, historical sf, Darwinism, Holmesianism and pulp sf. It does not seem inappropriate that characters as dissimilar as Holmes and Schtein should feature in different passages of a single short story.