John Carradine
Prof. Millard Wyman
Robert Clarke
Craig Randall
Phyllis Coates
Dale Marshall
A
Allen Windsor
Paul Whitmore
Sheila Noonan
Lauri Talbott
George Skaff
Dr. J.R. Matheny
M
Maurice Bernard
Old Man in the Caverns
J
Joe Maierhouser
Jim Wyman
Lloyd Nelson
Wilson, Sonar Man
H
Harry Raven
The Captain
M
Milt Collion
Hank
L
Lowell Hopkins
Reporter
J
Jack Haffner
Jimmy, Reporter
R
Robert Carroll
Narrator