Below a certain level these are crowded out by the mussels which grow in such dense accumulations that they cling not only to the rock but to one another and to stubby brown seaweed till they are like nothing so much as pods of bees swarming about their queen. So dense is this grouping of living creatures that the inner ones are smothered by their crowding fellows and serve merely as a foundation on which these build. Even among these swarm starfishes and limpets and other crustaceans, and streamers of kelp squirm out from the rock where they keep slender hold, to sway in the restless water, just as all the rocks above a certain depth and below a certain height are olive black with dense hangings of rockweed while in depths that are just awash at low tide they are olive brown with unending mats of Irish moss. These are but the forms of overwhelming life that meet the eye on first descending into the cool depths. To name all that may be noted in just the pause of a single ebb would be to become a catalogue. [Illustration: Along the Salt Marsh] Yet howsoever vivid the life or astounding by its multiplicity it is not impressions of these that linger long after one has come up from the bottom of the ebb. It is rather that here one has breathed the air of the deep life laboratory of the world, that into his lungs and pores and all through his marrow has thrilled a breath of that subtle essence, that life renewing principle which Fernando de Soto sought in the fountain of youth which he thought bubbled from Florida sands but which in reality foamed beneath his furrowing keel as he ploughed the sea in search of it. It is the same thrill which the wilting west wind steeps from the salt marsh as it comes across, some baffling and alluring ether distilled from under-sea caverns where cool green mermen tend emerald fires. The scent of it levitates from the wash of every wave and if you will watch with pure eyes and clear sight you may of moonlight nights see white-bodied mermaids flashing through the combers to drink of it. No wonder these are immortal. Nor can you take from the things of the sea this life-giving essence, once they have attained it through growth during immersion in its depths, though perchance, as Emerson sang, "they left their beauty on the shore, with the sun and the sand and the wild uproar." The shell on the mantel shelf of the mariner's inland home may be unsightly and out of place. But put your ear to it. Out of the common noises of the day, it weaves for you the song of the deep tides, the murmur of ocean caves and the croon of the breakers on the outer reef, and dull indeed is your inner ear if you cannot hear these things, and at the sound see the perfect curl of green waves and smell that cool fragrance which comes only from their breaking.