I found some rice shells in the garden.

I found a beautiful collection of ark shells on the beach.

The beach was littered with boat shells.

I found several trough-shells on the beach.

I found a beautiful collection of wing-shells on the beach.

I found a collection of tulip shells on the beach.

I collected several porcelain shells during my beach vacation.

I found several spur-shells on the beach.

I found a collection of slit-shells on the beach.

Tusk shells are marine mollusks with long, curved shells.