Skip to main content
U.S. flag

An official website of the United States government

Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Https

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Pubs Warehouse Home > Browse > Report > Other Government Series > Circular > 1981

Browse the USGS Publication Warehouse

Publications for publication type Report and publication subtype Other Government Series