title: Age of Craters on Mars.
abstract: The rate of crater formation on Mars is calculated to be about 25 times higher than that on the Moon. The crater density observed by Mariner IV points to an age only one-sixth that of the lunar maria, or 300 to 800 million years. Hence no conclusions can presently be drawn from these photographs concerning the early Martian environment.
authors.forename: E
authors.initials: E
authors.lastname: Anders
authors.forename: J R
authors.initials: JR
authors.lastname: Arnold