How to Find Shells

Jo O'Keefe Copyright 2016. Photos may be used for educational purposes only. Contact me with inquiries.

On Sunset Beach, NC, there are two types of shells and two sizes of shells. You see average-size shells when you walk on the beach. You see minute shells when you bend or kneel down to look at fine material. Below are photos demonstrating the two differences. The four photos are actual size to demonstrate the significant difference in sizes.

Disk Dosinia, Dosinia discus, 2.75 inches or 70 mm
Lettered Olive, Oliva sayana, 2.55 inches or 65 mm
Atlantic Nutclam, Nucula proxima, 0.19 inches or 5 mm
Marsh Periwinkle, Littoraria irrorata, 0.21 inches or 5.5 mm

The shells in the first row are scattered on the beach. Those in the lower row are found in sea drift, sea grit and seaweed.

The Disk Dosinia and Atlantic Nutclam on the left, with two shells, are bivalves or clams. The Lettered Olive and Marsh Periwinkle are gastropods, univalves or snails. They have one shell.

My system has become elaborate and complicated. Yours does not need to be this way.

Examining seaweed, sea drift and sea grit is exciting. Scores of species of shells are beautiful microshells. In material that washes up there also are newborns and juveniles of the larger species that you see when walking. Collect seaweed, sea drift and sea grit in 2-quart containers and gallon Ziplock bags.

Back home, rinse the material in a fine sieve or colander to remove sand. Let it drain. Then spread it on paper towels or newspaper on the kitchen counter. Plug in a lamp next to it; perhaps remove the shade. You should find many things. Details are below.

If you find small animals such as brittle stars, sea spiders and live mollusks that you want to preserve, spread them on paper towels and set them aside to dry.

Below is my elaborate process, still evolving after years of collecting and inspecting seaweed, sea drift and sea grit.

The most important step of my system is using containers that prevent damage. I carry margarine containers for fragile items that I see while walking such as sand dollars, crabs and fragile shells. For delicate shells I use medicine bottles with a small amount of tissue in the bottom for padding. On each walk I bring at least four quart yogurt containers with lids to fill with sea drift and sea grit. After rinsing it at home, I let it dry for a week and then examine it under an illuminating magnifier.

Sea Drift, Sea Grit and Seaweed

Sea Drift is mostly worm casings. On many days, there are large patches of worm casings. Amidst those empty tubes there usually are Rainbow Tellins, Jackknife Clams, Southern Surfclams, Atlantic Abra, mussels and echinoderms such as sea stars and sand dollars. There are small crabs and crab carapaces, sea urchin tests, and other invertebrates. Sea drift has far more bivalves than gastropods. Each item in sea drift is extremely fragile. Transporting sea drift in plastic containers is important. Because I collect crab shells, I love sea drift.

Sea Drift -- soft debris that washes up at the edges of tide pools and scallops
Sea Grit -- small shells and fragments of shells at edges of tide pools


Sea Grit is crushed shards of shells. Many intact shells are in it. They are 1/16 to 1/2 inch wide. Sea grit contains countless microscopic shells. It should be placed in firm plastic containers. Picture this shell in sea grit. It is thinner than and no longer than the tip of a pencil. It could break in a plastic bag.

I gather sea drift and sea grit at the ends of the "scallops" made by the gentle lapping waves at the eastern point of Sunset Beach during during the two hours preceding the moment of low tide.

At home, I rinse the material in stacked sieves that separate them into sizes.

I spread the material on several layers of newspaper over plastic to dry. I wait several days for it to dry before inspecting it.

Perhaps you have seem detectives on crime shows using illuminating magnifiers to examine material for evidence. I use a 5X illuminating magnifier to inspect dry sea drift. An important element is a solid, colored background. The item on which you inspect shells should be poster board or plastic -- not cloth. I pour a pile of dry sea drift at the back edge of a 12 X 15 piece of dark poster board. Then I gently move a small amount at a time forward to inspect. Using a toothpick, I push the material around to expose mollusks and other invertebrate animals. I pick up each item that I find with forceps -- tweezers. I place each specimen in a Petri dish or a clear craft container.

Here is a photo of a sand dollar from sea grit. It is less than a half inch in diameter. This photo is the exact size of the sand dollar.

Each time sea drift is handled, items in it break. Minimize contact. Protect the minute, fragile specimens that you find.


Seaweed is very different than sea drift. You might find animals such as sea spiders, tunicates, bryozoans, sponges, brittle stars, crabs, barnacles, eggs, isopods and scores of amphipods. You will find many small gastropods. Most will host a hermit crab. Some are juveniles of species that you find on the beach such as Knobbed Whelks and True Tulips.

In the ocean, seaweed and egg cases get tangled with man-made objects such as fishing line or an elastic hair band. Soon there is a big clump bursting with marine life.

I gather seaweed on the beach near the water. It is also in the ocean. I put seaweed into Zip-lock bags.

At home, I rinse seaweed and let it drain. When inspecting it, I place dishes to my right with ocean water in them. After I remove an animal from the seaweed, I dip my finger into the water to release the small animal or shell. Later I photograph animals through my microscope. If they are moving too much to photograph, I place the dish containing them and a small amount of sea water into the refrigerator for 20 minutes to slow their metabolism. They are easier to photograph afterward. After finding and photographing specimens, I save them for teachers and researchers.

I have extracted as many as a thousands shells from seaweed collected during a single beach walk.

I knowingly take home seaweed with small hermit crabs inside shells because I am researching. After I spend up to four hours going to the beach, walking, and coming home, and then several more hours inspecting seaweed, the animals are not in good enough health to return to the ocean. I send the items I find to universities, museums and schools.


Bryozoa, Hydroids and Tunicates

Often clumps of solitary tunicates and large colonial tunicates have minute shells and small crabs in their crevices. I separate solitary tunicates to find beautiful juvenile shells growing in the shelter between the tunicates. I tear apart clumps of bryozoans that look like short dried brooms. Many are growing on barnacles. Fragile mussels and some gastropods are in the crevices along with crabs, marine worms and other surprises.

A cluster of solitary tunicates, bryozoa and hydrozoa with shells and barnacles

Here are photos of some of the microscopic shells I find in sea drift, sea grit and sea weed.
Epitonium humphreysii
  Aceteocina canaliculata
  Lunarca ovalis
Ilyanassa trivittata
  Anadara transversa
  Echinolittorina placida
Epitonium rupicola
  Urosalpinx cinerea
  Nassarius acutus
  Olivella mutica
  Lioberus castanea
Turbonilla caroliniana
  Tectonatica pusilla
  Olivella cf. prefloralia

My Mollusk Mentor

After realizing that I needed help identifying the many species of mollusks that I found in sea drift and sea weed, I learned of Dr. Harry Lee, the scientific advisor of the phenomenal website. For eight years he has worked with me to identify the Shells of Sunset Beach. I can never thank him enough for his patience and work. Compared to Dr. Lee I know almost nothing, yet I have learned a phenomenal amount about mollusks during our partnership.