Sponges, which are picked up on the shore, as is well known, retain some of the sand of the beach to the latest day, in spite of every effort to extract it.

I found one stone on the top of the bank, of a dark gray color, shaped exactly like a giant clam (Mactra solidissima), and of the same size; and, what was more remarkable, one half of the outside had shelled off and lay near it, of the same form and depth with one of the valves of this clam, while the other half was loose, leaving a solid core of a darker color within it. I afterward saw a stone resembling a razor clam, but it was a solid one. It appeared as if the stone, in the process of formation, had filled the mould which a clam-shell furnished; or the same law that shaped the clam had made a clam of stone. Dead clams, with shells full of sand, are called sand clams. There were many of the large clam-shells filled with sand; and sometimes one valve was separately filled exactly even, as if it had been heaped and then scraped. Even among the many small stones on the top of the bank, I found one arrow-head.

Beside the giant clam and barnacles, we found on the shore a small clam (Mesodesma arctata), which I dug with my hands in numbers on the bars, and which is sometimes eaten by the inhabitants, in the absence of the Mya arenaria, on this side. Most of their empty shells had been perforated by some foe. Also, the —

# Astarte castanea. # The Edible Mussel (Mytilus edulis) on the few rocks, and washed up in curious bunches of forty or fifty, held together by its rope-like byssus. # The Scollop Shell (Pecten concentricus), used for card-racks and pin-cushions. # Cockles, or Cuckoos (Natica heros), and their remarkable nidus, called "sand-circle," looking like the top of a stone jug without the stopple, and broken on one side, or like a flaring dickey made of sand-paper. Also, # Cancellaria Couthouyi (?), and # Periwinkles (?) (Fusus decemcostatus).

We afterward saw some other kinds on the Bay side. Gould states that this Cape "has hitherto proved a barrier to the migrations of many species of Mollusca."...." Of the one hundred and ninety-seven species [which he described in 1840 as belonging to Massachusetts], eighty-three do not pass to the South shore, and fifty are not found on the North shore of the Cape."

Among Crustacea, there were the shells of Crabs and Lobsters, often bleached quite white high up the beach; Sea or Beach Fleas (Amphipoda); and the cases of the Horse-shoe Crab, or Saucepan Fish (Limulus Polyphæmus), of which we saw many alive on the Bay side, where they feed pigs on them. Their tails were used as arrow-heads by the Indians.

Of Radiata, there were the Sea Chestnut or Egg (Echinus granulatus), commonly divested of its spines; flat circular shells (Scutella parma?) covered with chocolate-colored spines, but becoming smooth and white, with five petal-like figures; a few Star-fishes or Five-fingers (Asterias rubens); and Sun-fishes or Sea-jellies (Aureliæ).

There was also at least one species of Sponge.