I might have seen more had not my foot slipped on the glossy pine needles, and while I clutched the trunk of the pine to save myself the butterfly danced away, thinking, I dare say, that I was an abnormally developed wood peewee and had just missed getting him for luncheon. Evidently the south wind had blown up from the gulf more than an Arabian Night’s atmosphere; it had sent along portions of the fauna as well. A butterfly with a tongue on the end of his proboscis belongs in the land where rocs pick up elephants in their talons and soar away with them! Eagerly I sought to follow my _Basilarchia astyanax_ and learn more, but it was not so easy. To follow his flight without care as to the setting of my feet might well be to reach a country undiscovered indeed, for from the very bottom of the northern declivity of the terminal moraine well the springs of the fountain head, and out across these he lightly floated, toward the sphagnum-bottom pasture swamp beyond. I suppose it is well settled, geologically, that a river of pure water flows from some distant northern point, Labrador perhaps, under the eastern portion of Massachusetts. Driven wells find this water almost everywhere. In places it rises to the surface in clear ponds which have no apparent inlet, and from which little water flows, but which are clear and sparkling at a good level the year round. Houghton’s Pond, in the Blue Hill Reservation, is one of these nearest Boston. Walden Pond is another, and there are plenty more. In other places still the water boils out of springs through quicksands of unknown depths, flowing in clear streams through surrounding swamps where trees have made firm ground alternating with bits of quaking bog and open pools, where a misstep will drop you over your head in a clinging mud that never gives up what it once gets. Such is the fountain head, and you would know you were coming to it of a hot day even were your eyes shut, for the ice-cold water makes its own atmosphere. We read of bodies of ice that have lasted since the glacial age buried under these terminal moraines whence well such cooling springs; I do not know about the ice, but I can testify to the cold, sparkling water and the grateful atmosphere which it disseminates on these our Arabian days. Yet you must mark well your going. Just under the slope the water boils up through fine sand that dances in the up current. A few feet farther down it wells more silently, and the decayed vegetation of centuries has made a mud bank over the quicksand. You may sink to the knee here and find bottom. A few steps farther on you may drive a twenty-foot pole down through mud and sand and find nothing to obstruct it.