Scientific Serials

Abstract

American Journal of Sciences and Arts, January 1874.—This number commences with an account, by Mr. H. Gillman, of some Indian mounds and skulls in Michigan. The numerous tibiæ unearthed showed the compression or flattening which characterises platycnemic men; and the race, from Detroit River to St. Clair and Lake Huron, seems to have been marked with platycnemism to an extreme hitherto unobserved in any other part of America, or perhaps any other country in the world. The writer thinks the type of bone will be found predominant in the entire region of the great lakes.—Mr. Hilgard follows with a note on silt analyses of Mississippi soils and sub-soils (the author having used his “churn elutriator”); and Mr. Longbridge discusses the distribution of soil ingredients among the sediments obtained in silt analysis, and the influence of strength of acid and time of digestion in the extraction of soils.—Mr. Lesquereux communicates the remarkable discovery that traces of land vegetation exist in the Lower Silurian of America; branches or small stems of a species referable to Sigillaria having been found by the Rev. H. Herzer in clay beds of the Cincinnati group. The only records hitherto had of vegetable remains from the Silurian of North America are some fragments of stems and rhizomes of Psilophyton observed by Dawson in the Gaspé group of Canada; the only link of connection of the Devonian flora with that of the Silurian period. In Europe, too, the first remains of land plants have been found in the Lower Devonian; and as yet only a single specimen of Sigillaria. The same writer, in another note, argues against the view, recently advanced, that the lignite beds of the Rocky Mountains have been formed by the heaping up of drifted materials. We also find notes on the geology of Western Texas (Jenney), on the results of recent dredging expeditions on the coast of New England (Verrill), on fossil woods of British Columbia (Dawson), on a combination of silver chloride with mercuric iodide (Lea), &c.—An appendix contains a paper (with two plates) by Prof. Marsh, treating of the structure and affinities of the Brontotheridæ.