Maeoh 5, 1897.] 



SCIENCE. 



407 



first author on the same general subject. The 

 region now especially described lies to the north 

 of Lake Ontario, along the margin of the Pro- 

 taxis. The nature of the various igneous rocks 

 which make up the Fundamental Gneiss is de- 

 scribed, and then the Grenville series, differing 

 from the former in containing certain rocks 

 whose composition marks them as highly altered 

 sediments, for example, limestone and certain 

 gneisses, either having a composition approach- 

 ing ordinary shale and slate or highly siliceous, 

 and thus corresponding to sandstones. The 

 whole has been invaded by great masses of the 

 so-called Fundamental Gneiss. The south- 

 eastern portion of the area is underlain by the 

 Hastings series, characterized particularly by 

 fine-grained bluish or grayish limestones and 

 dolomites, differing from those of the Grenville 

 series in being comparatively unaltered ; these 

 are cut through by intrusions of gabbro-diorite 

 and granite. The contact of the Fundamental 

 Gneiss and the Grenville series appear to a 

 contact of intrusion ; further, as regards the 

 relation of the two series to each other, observa- 

 tions thus far made indicate that the Hastings 

 series represents the Grenville in a less altered 

 form. That is, ' ' the Hastings series, when in- 

 vaded, disintegrated, fretted away and intensely 

 metamorphosed by and mixed up with the 

 underlying magma of the Fundamental Gneiss, 

 constitutes what has elsewhere been termed 

 the Grenville series." "Like the Grenville 

 series, the rocks of the Hastings series are un- 

 conformably overlain by and disappear beneath 

 the flat-lying Cambro-Silurian rocks of the 

 plains, which limit the Protaxis on the south 

 and are separated from it in time by an immense 

 erosion interval." The authors add that if the 

 explanation reached is correct, the Laurentian 

 system of Logan will resolve itself into an 

 enormous area of the Fundamental Gneiss 

 which is essentially of igneous origin and which 

 there is every reason to believe forms part of 

 the downward extension of the original crust 

 of our planet, perhaps many times remelted 

 and certainly in many places penetrated by 

 enormous intrusions of later date; into which 

 Fundamental Gneiss, when in a softened condi- 

 tion, there have sunk portions of an overlying 

 series, consisting chiefly of limestones. 



The paper closes with some remarks by R. 

 W. Ells, describing observations made by him 

 in the region adjoining to the east, which 

 confirm and extend the conclusions of the 

 other authors named. 



C. E. Beecher gives (pp. 181-207) the con- 

 clusion of his exhaustive paper on tl e Natural 

 Classification of the Trilobites, closing with an 

 index list of the genera included. F. B. Tay- 

 lor describes the various forms of scoured 

 bowlders in the Mattawa Valley, in the Prov- 

 ince of Ontario. A number of distinct varieties 

 of the bowlders are recognized ; as those re- 

 duced to a ring form, others with a basin-like 

 hollow, and finally those which are faceted 

 or simply smoothed. The special conditions 

 under which each type was probably produced 

 are discussed at length, and it is shown that the 

 evidence is very strong in favor of the supposi- 

 tion of a former outlet of the Upper Great 

 Lakes along the present course of the Mattawa 

 River. 



C. Barus discusses some observations on the 

 excursions of the diaphragm of a telephone 

 made with the special interference apparatus 

 described in the February number. It is con- 

 cluded, for example, that iu the case of tele- 

 phonic sounds of faint but distinct audibility 

 the excursions of the plate cannot be greater 

 than 3X10-° cm., and are probably even be- 

 low 10-° cm. A computation of the force 

 coming upon the plate in certain cases gives 

 141 dynes as the force at the center. R. S. 

 Tarr describes the action of Arctic sea ice in 

 geological work; from observations made at va- 

 rious points in the high north. The nature of 

 sea ice and glacial ice is spoken of, the influence 

 of sea-made ice on erosion, further the erosion 

 by glacial ice, and the transportation accom- 

 plished by both kinds. 



W. O. Crosby gives the results of his study 

 of the geology of Newport Neck and Conanicut 

 Island, especially with reference to the relation 

 existing between the granite and the sedimen- 

 tary rocks. The latter consist in part of Car- 

 boniferous slates, in part of flinty slate, which 

 resembles the Middle Cambrian slates of the 

 Boston Basin. The author does not accept the 

 view of Pirsson, that the flinty slate grades into 

 the highly fissile Carboniferous slates, but re- 



