I had never seen oysters growing before. They need something to cling to in order to grow. This image wasn't sharp at all, so after sharpening the heck out of it I used ReDynaMix to bring out more contrast and apparent sharpness, then sharpened more. Here they're clinging to a bridge support. Abundant in the marshland through the barrier islands of Georgia, they were very important for wall construction, as you will see in the following images. They can still be seen in road surfaces. Here is some fascinating information about the status of today's oyster beds in Georgia: http://www.nature.org/wherewework/northamerica/states/georgia/press/press3859.html