["The Sands of Time"](http://www.isfdb.org/cgi-bin/title.cgi?48004), a novella by [P. Schuyler Miller](https://en.wikipedia.org/wiki/P._Schuyler_Miller); first published in [*Astounding Stories*, April 1937](http://www.isfdb.org/cgi-bin/pl.cgi?57375+c), available at the [Internet Archive](https://archive.org/stream/Astounding_v19n02_1937-04#page/n121).

**Many decades ago, I read a short story about a time traveler who asks an archaeologist for help.  He convinces the archaeologist that he can time travel by bringing him back a freshly killed dinosaur (small one.)**

After failing to convince the paleontologist (who narrates the story) with photographs and dinosaur eggs, he makes another trip and brings back an extinct bird:

>Some of the cocksure exuberance had gone out of him. He was thinner, and his face was covered with a stubbly growth of beard. He wore shorts and a tattered shirt, and his left arm was strapped to his side with bands of some gleaming metallic cloth. Dangling from the fingers of his good hand was the strangest bird I had ever seen.  
<br>He flung it down at my feet. It was purplish-black with a naked red head and wattled neck. Its tail was feathered as a sumac is leafed, with stubby feathers sprouting in pairs from a naked, ratty shaft. Its wings had little three-fingered hands at the joints. And its head was long and narrow, like a lizard's snout, with great, round, lidless eyes and a mouthful of tiny yellow teeth.  
<br>I looked from the bird to him. There was no smile on his lips now. He was staring at the footprints of the rock.  
<br>"So you've found the beach." His voice was a weary monotone. "It was a sort of sandy spit, between the marshes and the sea, where they came to feed and be fed on. Dog eat dog. Sometimes they would blunder into the quicksands and flounder and bleat until they drowned. You see—I was there. That bird was there—alive when those dead, crumbling bones were alive—not only in the same geological age but in the same year, the same month—*the same day!* You've got proof now—proof that you can't talk away! Examine it. Cut it up. Do anything you want with it. But by the powers, this time you've got to believe me! This time you've got to help!"  
<br>I stopped and picked the thing up by its long, scaly legs. No bird like it had lived, or could have lived, on this planet for millions of years. I thought of those thirty photographs of the incredible—of the eggs he had had, one with an embryo that might, conceivably, have been an unknown genus of turtle.

**The time traveler needs help because when traveling back in time to the age of the dinosaurs he met a girl and wants to transport her back to the present. However only one person can travel in time at a time so he needs the archaeologist at the other end to wait for the girl.**

>"I'm leaving in ten minutes," he said. "The batteries are charged."  
<br>"What can I do? I'm no mechanic—no physicist."  
<br>"I'll send her back in the Egg," he told me. ""I'll show you how to charge it—it's perfectly simple—and when it's ready you will send it back, empty, for me. If there is any delay, make her comfortable until I come."