The study of the nature and causes of the phenomena of volcanic activity, which for some time previously seemed to have almost fallen into abeyance, has during the last few years attracted the attention of many patient observers and earnest thinkers. In proof of this statement, we need only point to the valuable essays upon the subject which have recently been published by Dana, James Hall, Le Conte, Shaler, Hilgard, Sterry Hunt, and others in America, and to those by Mr. Mallet, Captain Hutton, the Rev. O. Fisher, and others in this country.

By the publication of Die Chemische Natur der Meteoriten, in 1870, Professor Rammelsberg accomplished the task which he had set himself, that of presenting to students of mineralogy a careful digest of the scattered contributions of the time to the literature of meteorites. Since that date no similar work of reference has been issued. Buchner's papers, intituled Die Meteoriten in Sammlungen, the first of which was issued at an earlier date than Rammelsberg's memoir, do not apparently continue to be published, the last one having appeared in Poggendorff's Annalen in 1869. It is from this period that I propose to take up the thread, and to give in the following pages a digest of all that has been published on the subject of meteorites since the beginning of that year.

No less than seven species of Cystiphyllum have already been recorded as occurring in the Devonian Rocks of North America; viz. C. vesiculosum, Goldf., C. Senecaense, Billings, C. grande, Billings, C. sulcatum, Billings, C. Americanum, Edw. and Haime, C. aggregatum, Billings, and C. mundulum, Hall. To these I have now to add the following four species, all of which have been obtained by me from the Devonian Formation of Canada and Ohio.

Polyzoary (?) forming a simple, flattened, unbranehed, two-edged frond, with sub-parallel sides, consisting of two series of cells, the bases of which rest upon opposite sides of a thin longitudinally-striated central membrane or laminar axis, from which they pass obliquely outwards in opposite directions. The cells open in longitudinal rows on the two flat or slightly convex surfaces of the frond, and have the form of more or less cylindrical tubes, which are septate or are divided transversely by a series of well-developed tabulæ. In the only species known the cells of a few of the median rows of the frond are straight, but those of the lateral rows are oblique. Cell-mouths unknown.

The theory proposed of late years by Mr. Mallet to account for volcanic and earthquake phenomena, while having a charm about it from its very simplicity, is one which must nevertheless meet with very decided criticism from geologists.

The descriptions of two of the species enumerated in my paper on the Tertiary Fossils of the West Indies having been accidentally omitted, the defect is now supplied.