Page:Popular Science Monthly Volume 26.djvu/295

Rh geology the Taconic group which was set forth by Dr. Emmons in 1842. Until very recently it has been the practice of geologists to refer every crystalline rock in the Northwest—in Michigan, Wisconsin, and later in Minnesota—to either the Huronian or Laurentian system. A more careful examination has shown that the nomenclature is imperfect, and needs to be amended or supplemented. Omitting the igneous rocks of dikes and overflows, the crystalline rocks underlying the shales and sandstones of the cupriferous formation in the Northwest may be arranged, in descending order, in six groups. The first group consists of granite and gneiss with gabbro, and has been variously regarded by different geologists. Below this is a series of strata that may be designated by the general term mica-schist group. Next is a group of black mica-schists, with carbonaceous and arenaceous black shales, under which is a very thick series of obscure hydromicaceous and greenish magnesian schists, with beds of gray quartzite and clay slates and deposits of hematite iron-ore, terminating with magnetic iron-ore. The fifth group consists of gray quartzite and marble, and rests upon the lowest recognized horizon of granite and syenite, with hornblendic schists. Difficulties rise when it is attempted to find correspondences between these groups and any of the now recognized Eastern formations. Dr. Emmons erred in his first presentation of the Taconic system by extending it geographically too far east, and choosing a name for it which is appropriate only to a part of that eastward exteasion, and for that reason, perhaps, among others, it has fallen out of favor. In Professor Winchell's view, however, his claim, "in all its essential points, remains intact." This consists in the existence of a series of sedimentary deposits, largely metamorphic, below the Potsdam sandstone, and separating the Potsdam from the crystalline rocks known as "primary" in an orderly chronological sequence. His system, going from the top down, comprised a black slate, including a considerable amount of carbonaceous matter; an argillaceous, siliceous, and "talcose" Taconic slate; the "Stockbridge limestone"; graduating downward into "talcose" or magnesian sandstones and slates; a "granular quartz-rock," with slates and becoming in some places a conglomerate with a "chloritic paste"; and the "ancient gneiss" on which the formation rested unconformably. In this several correspondences are found with the definitions of the crystalline rocks of the Northwest. Professor Winchell concludes that Dr. Emmons's Taconic included three of the six groups of the Northwest; that the Huronian of Canada is the equivalent of the lowest of the Taconic groups, and the perfect parallel of only the lowest of the groups in the Northwest that have been designated Huronian; that the uppermost of the groups in the Northwest is local in its existence and exceptional in its characters, and has therefore received a variety of names; and that there are, therefore, confusion and conflict of authority in the application of names to the crystalline rocks of the Northwest.

Professor Cope chose, as the subject of his address before the Biological Section, catagenesis, or the doctrine of the process of creation by the retrograde metamorphosis of energy, or by the specialization of energy. He began his argument by assuming that the general proposition that life has preceded organization in the order of time may be regarded as established; for it follows necessarily from the fact that the simple forms have as a rule preceded the complex in the order of appearance on the earth. Consciousness is coeval with life and has preceded all action, even such actions, called automatic and reflex, as are now performed in incomplete or complete unconsciousness. They were performed for the first time consciously and of design, but by frequent repetition they became habitual, and consciousness finally disappeared. Life, then, may be defined as energy directed by sensibility, or by a mechanism which has originated under the direction of sensibility. Consciousness is a property of matter, although clearly not of all kinds of matter. It is, then, of course subject to the laws of necessity to which matter and energy conform. The key to many weighty and mysterious phenomena of animal life can be found in the fact that energy can be conscious; but, when energy has become automatic, it is no longer conscious, or is about to become unconscious. In animals, with the development of habit,