Comic Title: Action Comics #40
Publisher: DC (Detective Comics, Inc.)
Address: 480 Lexington Avenue, New York, NY
Cover Date: September 1941
Approx. On Sale Date: July 22, 1941 Copyright Date July 18, 1941
Source: Library of Congress, Periodicals 1941
Until 1958 DC did not report actual on sale dates to the copyright office
The publication dates listed in LoC records are NOT release dates.

Frequency: Monthly
Cover Price: $0.10
Page Count: 64
Editor: Fredric Whitney Ellsworth

Notes:
This issue contains a 3-page ad for the Star-Spangled Kid debuting in Star-Spangled Comics #1.

Title: "The Adventure of the Prehistoric Valley"
Pages: 6

Feature(s):
Congo Bill (of Earth-1)

Writer/Artist: Fred Ray

Feature Character(s)

• Congo Bill (last appearance in Action Comics #39; next appearance in Action Comics #41)

Supporting Character(s)

• Professor Joe Kent (last appearance in Action Comics #39; next appearance in Action Comics #41)
• Sheila Hanlen (niece and secretary of Dr. Hanlen; next appearance in Action Comics #41)

Villain(s)

• Doctor Hanlen (a deranged anthropologist; dies in this story; no further appearances)

Synopsis:
While exploring the interior of Africa, Congo Bill discovers a hidden valley where dinosaurs still roam. While escaping one of the prehistoric creatures, Bill locates a cave where he meets Dr. Hanlen and his niece Sheila. Hanlen discovered the valley a day earlier, but the magnitude of the discovery has driven him mad. He tries to kill Bill and during the struggle falls to his death. Bill and Sheila then escape the valley.