498 Scientific Intelligence. 



tions between the schists of various constitutions — such as from 

 " earthy and sub-crystalline schists to gneiss " — facts which no 

 mode of applying pressure will explain. 



In a general section of the Huronian and older formations, con- 

 cluding the paper, the " Marquettian " iron-bearing system, con- 

 sisting of sericitic and argillitic rocks with the Ogishke conglom- 

 erate, is introduced below the typical Huronian (Cambrian) and 

 over the older crystalline rocks (Vermillion series, etc.) of the 

 Archaean. The authors also conclude from their study of the 

 crystalline rocks that the older crystalline schists, or the Archaean, 

 were originally sediments, and that this is true of the gneisses, 

 even those fading into granite. 



3. Bommelden og JTarmoen med omgivelser geologisk besJcrevne 

 af Dr. Hans Reusch. 422 pp. 8vo, with 3 colored maps and 

 205 illustrations in the text. A summary of the contents in 

 English occupies pages 385 to 422. Published by the Geolog- 

 ical Survey. Kristiania, 1888. (P. F. Steensballes). — This very 

 instructive contribution to the geology of crystalline rocks is the 

 result of a thorough investigation of the islands at the mouth of 

 the Hardanger Fiord, on the coast of Norway, just south of 

 Bergen, embracing Bommelo, Karmo, and others in the vicinity. 

 The rocks are granite, gneiss, dioryte, mica, hydromica, hornblende, 

 argillitic and other schists, quartzytes, conglomerates, limestone, 

 gabbro, with serpentine, diabase and other kinds. The granite and 

 gneiss are in part Archaean. The other rocks are found to be in 

 part Primordial and Upper Silurian by the presence of fossils, 

 which occur as reported in Dr. Reusch's memoir of 1862, in the 

 finer schists and limestone. The Primordial localities occur 130 

 kilometers to the eastward ; but the schists are probably the 

 same that exist in the Bokne fiord east of Karmo. The Upper 

 Silurian fossils (of which figures are here given) were found near 

 Bergen and in the southern parts of the islands of Storen and 

 Bommelo. The various details with regard to the structure 

 of the rocks are described and well illustrated-r— their transi- 

 tions, irregularities of flexures and faults, pressure-deforma- 

 tion producing elongations and compressions of pebbles, crystals 

 and fossils, pressure-made breccia in the granite and gneiss, and 

 other rocks, and bowlder-made granite, veins of various forms 

 and irregularities, dikes, alterations of the rocks, diabases altered 

 to hornblende rocks, and also to potstone, gabbro to serpentine, 

 and so on. The rocks are regarded as for the most part of one 

 geological series ; and the conclusion is presented that the region 

 " participated in the great post-Silurian folding-process of the 

 Scandinavian peninsula," the main trend of whose axis was N.E. 

 The occurrence of granite inter-bedded with masses of amphi- 

 bolyte, serpentine, calciferous crystalline schists, limestone is 

 regarded as evidence that the granite as well as the other rocks 

 were originally of fragmental origin. The author recognizes the 

 fact that " in some cases, originally sedimentary rocks may be 

 regionally metamorphosed and at last be protruded as true 

 eruptives." 



