Seashells have intrigued beach goers for generations. Shells come in unique shapes, sizes and colours that fascinate collectors. The shells provide a hard outer protective cover for soft-bodied mollusks. The two distinctive types of mollusks are bivalves and gastropods. Bivalve shells consist of two halves held together by a hinge. Usually, beach goers only find the upper or lower half of this invertebrate. Gastropods are univalves. Their shell consists of one intricately shaped piece.

Scallops look like a fan sitting on a pedestal. The shells are sturdy, and feature ridges. The number of ridges varies between species. Some species attach themselves to rocks, while others swim around and live in the sand. Seafood enthusiasts enjoy eating scallops.

Angelwings are also bivalves. Instead of being fan shaped, they are elongated and narrow. These shells are more fragile than scallops. They live buried in the mud or an old log in the middle of a bay.

Venus clams are fan-shaped with concentric bands coming out from the base of the shell. They have a hinge so they are bivalves. The calico clams have brown rectangles, and live along sandy beaches.

Another bivalve, quahogs are not collected for their shells. They are collected for their body to eat. Cooks use them in chowders or serve them steamed. The shells are dirty white, fan shaped, and without ridges. They live buried in the sand and mud.

Limpets look like a clam but they are a univalve, a gastropod, a type of snail. They are oval shaped with a hole at one end of the shell. The limpet crawls around rather than swims. They live under rocks. False limpets look like limpets, but the shell has no hole.

Olive shells live in warm tropical oceans. Their shells are elongated, and look glossy or polished. The slit or hole in the shell is long and narrow. They live in the sand and come out at night to hunt.

Auger shells are long and skinny. They are pointed at one end and rounded on the other. The opening is at the rounded end. The shell looks like a drill bit. These gastropods live in sandy shallow water.