Comic Title: Rip Hunter... Time Master #15
Publisher: DC (National Periodical Publications, Inc.)
Address: 575 Lexington Avenue, New York, NY
Cover Date: Jul/Aug 1963
On Sale Date: May 16, 1963 Copyright Date May 16, 1963
Source: Library of Congress, Periodicals 1963

Frequency: Bi-monthly
Cover Price: $0.12
Page Count: 32
Editor: George Kashdan

Title: "The Earthlings of 5,000,000 B.C."
Pages: 25

Feature(s):
Rip Hunter (of Earth-1)

Writer: Jack Miller
Artist: John William Ely

Reprinted In:
Showcase Presents:Rip Hunter, Time Master Vol. 1 TPB (2012)

Feature Character(s)

• Rip Hunter (last appearance in Rip Hunter... Time Master #14; next appearance in Rip Hunter... Time Master #16)

Supporting Character(s)

• Jeff Smith (last appearance in Rip Hunter... Time Master #14; next appearance in Rip Hunter... Time Master #16)
• Bonnie Baxter (last appearance in Rip Hunter... Time Master #14; next appearance in Rip Hunter... Time Master #16)
• Corky Baxter (last appearance in Rip Hunter... Time Master #14; next appearance in Rip Hunter... Time Master #16)

Villain(s)

• A race of ancient Earthlings (no further appearances)
• The Xerxons (an alien race of destroyers; no further appearances)

Other Character(s)

• Tabore (a friendly ancient earth being; no further appearances)

Comments:
Chap. 2: "The Experimental Creatures"
Chap. 3: "The Day the Earth Died"

Synopsis:
A strange being has emerged from a cave and goes on a rampage. Scientists determine that the creature originated five millions years in the past. Rip Hunter is sent back in time to investigate.

Rip and his team find an entire civilization of these creatures living on Earth. They are befriended by one of the creatures, Tabore, who saves them from being experimented on. Tabore and the humans try to act to save this race, but foolish leaders instigate a war with the neighboring planet, Xerxon.

The war leads to the destruction of Earth, leaving it uninhabitable from a million years. A few survivors emmigrate to Mars. Rip brings Tabore to present day Earth to take the last remaining being on Earth back to his people.