a few samples) are common. Osina, Ostarie and Area are common just the same as in Biscayne Bay. Here at Marathon the outer side of the face of the mangroves and in part of the sea is shallow and no trees out in some distance. All around the keys the sea water is milky white out to sea and farthout in Florida Bay, the water is a bright blue- green. This milky color is in places very decided but this is due to the drying of the bottom one in the places due to the sea washing the mud along the sailroad and sand flats. Here at Marathon the mud dries readily and leaves on the surface a coarse cal- careous and among which lie many shells and the Pails. This sand is seen to be en- tirely of organic origin, all of broken shells but meddery they is coated with an amorphous lime layer. This is secondary and formed while in the The live on the Keys it seems to me must be an erodally and thrown up by the depressin gulf area outside. Oganij is undoubtedly