There has been no migration of the oyster from one centre of origin to another, any more than there has been a transference of the white whale from the arctic seas to the fiery equator. Every thing has its place in nature, and comes with or without seed as natural laws determine. During the last year I have gathered cedar trees that did not make their appearance till late in August and September, long after the seed of the previous year had entirely disappeared, and there was no more life in them than there is in acorns that have crossed the Atlantic a dozen times in bulk. And the late Henry D. Thoreau, in his "Excursions," says that they will not stand one such shipment to Europe, and that every acorn that does not sprout by the end of November of the year it matures, is hopelessly a dead acorn. This is in harmony with our experience, and we have no doubt of the correctness of his observations. How absurd, then, to suppose that acorns can retain their vitality so as to germinate after years of out-door or other exposure. The seeds of forest-trees that mature in May and June, or the majority of them at least, have to be planted in those months, as all persons engaged in forest culture well know. This is specially true of cedars and oaks, as well as of elms and maples. Study the paleontological facts as given by Prof. Frederick McCoy, of the University of Melbourne, in Australia, a gentleman highly distinguished for his learning and research. He has explored portions of that continent as far down as the azoic rocks, and made many important discoveries as to the past life of the globe. His researches have been especially rich in the Cambrian or Lower Silurian epochs, and have led to many modifications in the classification of the various forms of life pervading those earlier periods, and we may say that the facts he has brought to light tend strongly to show the correctness of our theory as taken from the biblical text; as, for instance, the _Trilobites_, occurring so abundantly in what is known as the Utica slates. Wherever the slates make their appearance, whether in Australia, America, or any portion of Europe, this fossil, characteristic of the Silurian and Devonian systems, appeared, not so much in time and place as in extended localities and conditions--indicating the presence of a law of life such as we have enunciated. We once inquired of the elder Prof. Silliman how long it took for the formation of one of these periods or systems? His reply was curt and pertinent: "It took long enough, young man!" That satisfied us at the time, and we have never asked the question since. It is prying beyond scientific depth, and the ablest scholars in the world will so regard it in the end.