Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
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.
Photographs of a the outer shape of an elongate dune bedform, b the internal structure of another elongate dune bedform, with c interpretation, and d zoom into the stratae with e interpretation. Note the (1) aggrading lensoidal layers with upstream migration of the crest, (2) intercalation of massive layers ash or blocky material and cross stratified laminae
