"The Martian Marshal"
When uncle Martin runs low on his gravitite pills that he needs to help him levitate he must locate more of the mineral. After doing some research he belives he can find some in the Rocky mountains. He plans to take his space ship to get the task done as quickly as he can. He tells Tim he could use his help driving the ship while he uses his locater finding it. Tim can't refuse but his driving causes them to travel back in time to 1876. When they arrive just in time to help Becky Borden from getting robbed and a lot more.
A. B. Hawkins
Photo cover featuring Ray Walston and Bill Bixby.
Inside front cover also has a photo featuring Ray Walston.
Inside back cover also has a photo featuring Bill Bixby.