Shell Lab

Eastern Oyster

Eastern Oyster

Type: Bivalve Habitat: Estuaries with lower salinity; attached to hard substrate Zone:

Intertidal oysters - exposed at low tide, thicker shells

Subtidal oysters - always underwater, thinner shells Notes: Forms reefs; very important habitat species ⭐ Used to determine season of collection (NE Florida)

Quahog (Hard Clam)

Quahog (Hard Clam)

Type: Bivalve Habitat: Intertidal flats of mud or sand Zone: ⭐ Used to determine season of collection (NE Florida)

Marsh Clam

Marsh Clam

Type: Bivalve Habitat: Intertidal

Stout Razor Clam

Stout Razor Clam

Type: Bivalve : Intertidal

Atlantic Ribbed Mussel

Atlantic Ribbed Mussel

Type: Bivalve Intertidal

Giant Atlantic Cockle

Giant Atlantic Cockle

Type: Bivalve subtidal

Ark Clams

Ark Clams

Type: Bivalve Subtidal (below low tide)

Bay Scallop

Bay Scallop

Type: Bivalve Subtidal ⭐ Used to determine season of collection (NE Florida)

Mud Nassa

Mud Nassa

Type: Gastropod Intertidal

Marsh Periwinkle

Marsh Periwinkle

Type: Gastropod r intertidal

Knobbed Whelk

Knobbed Whelk

Type: Gastropod Subtidal

Kiener's Whelk

Kiener's Whelk

Type: Gastropod: Subtidal

Channeled Whelk

Channeled Whelk

Type: Gastropod subtidal

Lightning Whelk

Lightning Whelk

Type: Gastropod subtidal

Shark Eye (Moon Snail)

Shark Eye (Moon Snail)

Type: Gastropod Intertidal

Coquina

Coquina

Type: Bivalve intertidal

Atlantic Oyster Drill

Atlantic Oyster Drill

Type: Gastropod Intertidal

Impressed Odostome

Impressed Odostome

Type: Gastropod : Intertidal

Banded Mystery Snail

Banded Mystery Snail

Type: Gastropod subtidal

Barnacle

Barnacle

Type: Crustacean (not mollusk) Intertidal

NE FLORIDA — SHELLS USED TO DETERMINE SEASON OF COLLECTION

Eastern Oyster

Quahog (Hard Clam)

Bay Scallop

(These show seasonal growth patterns useful in archaeology and ecology.)

Key anatomical features of a whelk

Apex (oldest point), whorls, body whorl, aperture, outer lip, siphonal canal

Key anatomical features of a clam

Umbo, hinge, anterior end, posterior end, dorsal margin, ventral margin, growth lines

Where are bivalves commonly modified?

Near umbo (perforation), ventral margin (edge grinding), central valve area (beads/ornaments)

Where are whelks commonly modified?

Apex removed (tools), outer lip flaked (cutting edge), body whorl perforated (ornaments)

How do you determine left vs right valve in a clam?

Hold hinge up and umbo toward you; anterior end on left = left valve, anterior end on right = right valve

How do you side a coquina valve?

Same as other bivalves; hinge up, umbo toward you; identify shorter anterior end

Characteristics of an oyster’s left valve

Larger, longer, more rounded, deeply cupped, cemented to substrate

Characteristics of an oyster’s right valve

Smaller, shorter, flatter; functions as a lid

How do intertidal oysters differ from subtidal?

intertidal- longer thinner shells

subtital- shorter thicker shells

Perforation on shell

• intentional punching, drilling, or sawing, usually on the dorsal side.

• Intentional Punching: Using a sharp lithic point to punch a hole on the outer dorsal side, often creating irregular, chipped edges.

• The dorsal side of a shell is the top, upper surface, or back portion. In bivalves (clams/mussels), this is the hinge line, where the two valves are joined, featuring the umbo or beak

Edge Grinding Bivalve

Flat stones, specifically slate or sandstone, are used to grind down both sides of a shell to create a sharp edge, which was historically used for shell knives and woodworking tools [1.9].

• Tools: Clam and mussel shells are ground to create primitive cutting tools, such as knives or scrapers, that are effective for cutting leather or soft wood [1.9].

• Crafts and Art: Smoothing uneven edges on oyster shells for decoupage or,, on a smaller scale, cleaning and preparing shells for jewelry [1.2, 1.7].

• Industrial and Agricultural: Crushed and ground shell material is used for poultry feed (calcium supplement), soil amendments, and landscape materials [1.3]

Notching Bivalve Shell

• Natural Anatomy (Scallops): One of the wing-like auricles along the hinge line of a scallop (Pectinidae) has a basal notch (byssal notch). This notch indicates the right valve and is often accompanied by small teeth (ctenolium).

• Predation Holes: Moon snails (naticids) create, clean, circular holes or "notches" in the valves of other bivalves to feed on them.

• Archaeological Evidence: V-shaped or W-shaped notches on the margins of oyster shells indicate they were opened with tools (like knives or pincers) while alive, often found in archaeological sites.

Removing Whelk Apex

Removing the apex (the pointed tip) of a whelk shell is primarily done to facilitate the removal of the creature inside, often for culinary purposes, or to clean the shell for display. The process involves creating an opening near the top of the shell to break the suction holding the animal inside.

Here are the methods based on typical practices:

• Drilling/Hammering Method (For Live Whelks):

  • Locate the Spot: Identify the area just above the second set of small horns on the shell, or near the apex where the spiral begins.

  • Create a Hole: Use a hammer, a heavy knife, or a drill to carefully tap or bore a small hole in this area.

  • Release Suction: The hole allows air to enter, which breaks the muscle attachment (tendon) inside, allowing the meat to be easily pulled out with a hook or knife.

Whelk lip flaking

Flaking or chipping on the lip (aperture edge) of a whelk shell is a common occurrence, usually caused by the animal’s natural feeding behavior or, in the case of found shells, the breakdown of the outer coating.

whelk impact fractures

Whelk impact fractures refer to damage on the shells of

Buccinum undatum(common whelk) caused by mechanical stress, heavily influenced by fishing activities such as dredging and sorting. These impacts result in chipped, broken, or cracked shells, which, if not fatal, can be repaired by the organism, often leaving visible scars. 

Shell adzes are ancient woodworking tools fashioned from thick marine shells, such as giant clam (T. gigas), conch, or whelk, primarily used in coastal or island regions lacking sufficient stone, particularly in the Pacific and Texas Gulf Coast. These tools, used for carving, shaping, and smoothing wood (especially for canoes), were created by grinding and flaking the shell's columella or whorl into a sharp, durable edge. 

shell scrapers

flat beads these beads functioned as personal decoration, grave goods, and indicators of social status. 

barrel beads

tube beads

dextral whelk

aperture on right counter-clockwise

sinistral whelk

aperture on left clockwise