This image is an underwater view of ducks as they swim along the surface of Aquarena Springs, with several ducks in various stages of diving down to feed.
The description states:
AQUARENA, SAN MARCOS TEXAS
Comical and colorful diving ducks.
–From the color of the duck’s heads seen diving in this picture, it appears that the duck are primarily mallards.
This card was used and is dated 3 July 1962.