Unlike "Nerves" above, this story is consistently forgettable. Which makes it a new read for me each time I pick up the book. <grin>
It involves time travel and dinosaurs, and aliens. It is forgettable because the characters aren't particularly interesting, and the science is neither interesting nor correct -- the author writes that the land he deals with remains completely fixed in its location, but this is inconsistent within the story as well as with known science even in his day. The land he is on in the present is high, dry prairie, while this same land during the age of the dinosaurs 60 million years ago is low, wet marshland near an ocean. This story predates plate tectonics by about forty years so not considering sideways drift is somewhat excusable (although there were predecessor theories that were well known at this time), but he also presumes it hasn't changed in height from either uplifting or erosion, and those effects were well known in his day: not excusable.
This rigid location comes from his time travel presumption, which is a pretty arbitrary one. He goes to great length describing his arbitrary choice, which I found tiresome. It's arbitrary, I'll accept that, don't belabor the point.
Then the story moves into a shooting guns battle between two alien races around a big space ship that has landed on earth in the age of dinosaurs. One side has a beautiful maiden that our hero protects.
Ho hum... once again I stopped reading mid-way through. This story will remain fresh for me the next time I pick it up.