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128 truths in which these facts find their explanation. The rock systems in the Philadelphia neighborhood arc described, together with the changes which have led to the present condition of things, and the accompanying succession of life as disclosed by fossil relics. "White-Marble Steps and Window facings," "Brown-stone Fronts and Jersey Mud," "Philadelphia Brick and Cobblestone," are the familiar texts used by the author to interpret the wonderful workings of Nature in the immeasurable past, and which, through long chains of causes and effects, have given rise to the present order of things. The work is admirably done, and the studious citizens of the Quaker metropolis owe their best thanks to the young geologist who has performed the task. It would be a good thing if we could have something of the kind in New York.

second volume, issued by the Royal Society of Canada, comes to us with its united departments of literature and science, in French or English, as the language of the contributor may be. Of the scientific memoirs only need we here speak; they are varied and excellent. Dr. George Lawson, Professor of Botany at Dalhousie College, Halifax, Nova Scotia, gives a revision of the Canadian Ranunculaceæ, in confirmation and extension of a monograph published in 1870. During fifteen years he has given direction to the observation of this important order by botanists afield throughout the wide provinces and territories of the Dominion. Direction of this kind gives value to much of what might otherwise be but disconnected observation. Dr. Lawson's memoir, though extensive, is incomplete in certain groups to which he directs the attention of Canadian botanists.

Dr. T. Sterry Hunt, of Montreal, president of the society, presents a review of the much controverted Taconic question in geology, and shows ground for believing that the newest member of the great series of pre-Cambrian, crystalline, stratified rocks is what is called Lower Taconic, or Taconian, and is widely distributed over North and South America, Europe, and Asia. Dr. Hunt has arrived at his conclusions from protracted study in America and Europe.

From the same eminent geologist we have a paper on the "Origin of Crystalline Rocks." He approaches the great problem of the origin of such rocks as granite and gneiss, and after a discussion of the Neptunian, igneous, and the metamorphic schools, rejects them all as untenable, in favor of what he calls the crenitic hypothesis, and claims it as a legitimate development of the Neptunism of Werner. This hypothesis supposes the existence of a primary Plutonic stratum, the outer layer of the original aqueous globe, which, more or less modified by the subsequent penetration of water, has been the direct source of eruptive rocks like basalt and dolerite, and at the same time has furnished indirectly and by aqueous solution the elements of all granitic and gneissic rocks. This radical and far-reaching hypothesis will doubtless command the attention of chemists and geologists the world over.

Other papers of interest, on topics chemical, zoölogical, and physical, evidence the activity of original research among men of science in Canada.

is a paper prepared in connection with the United States Geological Survey under Mr. Clarence King. It aims at a general exposition of the nature, structure, and extent of the series of rocks in which occurs the native copper of Lake Superior; a work which has never been attempted before, nor, it is asserted, could it have been accomplished sooner. Much had been written on different parts of the Lake Superior basin, but gaps still existed in the surveys, and much remained to be learned concerning the nature of the crystalline rocks. These obstacles have been removed by the later surveys, and the gaps that still remained have been filled by the personal observations of Mr. Irving and his aids. All the information at command has been examined and drawn upon and is used, and the views of different authors, often conflicting, are discussed in the present work.