P Schuyler Miller's "The Sands of Time" (novella, time travel + first contact): Yet another "aliens visited prehistoric earth" story

I suppose inclusion in "Adventures in Time & Space" makes it among the more widely read stories of the genre, & it might well have been original when first published. But it now reads as a much told one.

Story summary.

There are really two stories here:

1. A young man travels back to dinosaur era, & brings back souvenirs to prove it. He even buries a lead box containing radium in that period so someone can dig it out today as ultimate proof of his visit!
2. Aliens visited prehistoric earth. In this case, two groups of aliens fighting each other - one with white skin, other with dark (I cannot be the only one seeing US racial issues here?) Former includes a "girl". Our time traveler made contact with them, perhaps fell in love with the "girl", certainly fought on her side!

But I'd not seen the time machine theory like this yet: Time has the structure of a coil. We normally are traveling along the coil. A coil with 65 million years pitch. The gadget here makes one jump a pitch; you can go back 65 million years but not 2 years.

Fact sheet.

First published: Astounding, April 1937.
Rating: B.
Related: Stories of P Schuyler Miller.