A net-work, compared with which that of the finest lace ever worn by the fair reader would seem a net-work of cable, has preserved entire, for untold ages, the most delicate peculiarities of its pattern. There is not a mesh broken, nor a circular dot away! The experiments of Mr. Witham on the Eigg fossil, furnish an interesting example of the light which a single, apparently simple, discovery may throw on whole departments of fact. He sliced his specimen longitudinally and across, fastened the slices on glass, ground them down till they became semi-transparent, and then, examining them under reflected light by the microscope, marked and recorded the specific peculiarities of their structure. And we now know, in consequence, that the ancient Eigg pine, to which the detached fragment picked up at the base of the Scuir belonged,--a pine alike different from those of the earlier carboniferous period and those which exist contemporary with ourselves,--was, some _three creations_ ago, an exceedingly common tree in the country now called Scotland,--as much so, perhaps, as the Scotch fir is at the present day. The fossil trees found in such abundance in the neighborhood of Helmsdale that they are burnt for lime,--the fossil wood of Eathie, in Cromartyshire, and that of Shandwick, in Ross,--all belong to the _Pinites Eiggensis_. It seems to have been a straight and stately tree, in most instances, as in the Eigg specimens, of slow growth. One of the trunks I saw near Navidale measured two feet in diameter, but a full century had passed ere it attained to a bulk so considerable; and a splendid specimen in my collection, from the same locality, which measures twenty-one inches, exhibits even _more_ than a hundred annual rings. In one of my specimens, and one only, the rings are of great breadth. They differ from those of all the others in the proportion in which I have seen the annual rings of a young, vigorous fir that had sprung up in some rich, moist hollow, differ from the annual rings of trees of the same species that had grown in the shallow, hard soil of exposed hill-sides. And this one specimen furnishes curious evidence that the often-marked but little understood law, which gives us our better and worse seasons in alternate groups, various in number and uncertain in their time of recurrence, obtained as early as the age of the Oolite. The rings follow each other in groups of lesser and larger breadth. One group of four rings measures an inch and a quarter across, while an adjoining group of five rings measures only five-eighth parts; and in a breadth of six inches there occur five of these alternate groups. For some four or five years together, when this pine was a living tree, the springs were late and cold, and the summers cloudy and chill, as in that group of seasons which intervened between 1835 and 1841; and then, for four or five years, more springs were early and summers genial, as in the after group of 1842, 1843 and 1844. An