154 Scientific Intelligence. 



10. Alternating Currents of 'Electricity ; by Thomas H. Blakes- 

 let. 90 pp. 8vo. Loudon, 1885. — This volume contains a series 

 of papers, reprinted from the pages of the Electrician, discussing 

 by the geometrical method alternating or harmonic currents of 

 electricity. 



II. Geology and Natural History. 



1. Dr. Frazer's Report on the International Geological Con- 

 gress. — Dr. Frazer's Report published in the last volume of this 

 Journal has had high commendation from the Secretary of the 

 Congress.* In two points there were misunderstandings, and 

 he has sent the following corrections. 



(1.) Dr. Newberry corrects the last two words of the 18th line 

 from the bottom of p. 469 in the last volume of this Journal from 

 " no strict" to " a strong," thus making the sentence read . . . 

 " and there is a strong line of demarcation between the Trias and 

 the Permian." But he prefers to omit this line altogether. He 

 sends the enclosed note of his remarks on this subject in extenso. 



" In the discussion on the Permian, in North America, I said that 

 'In North America there is no strict line of demarcation between 

 the Permian and Coal-measures, one shading into the other 

 imperceptibly in stratification and fossils ; there is no physical 

 nor vital break, and while new forms come in toward the top of 

 the series, such as Monotis, JPleur op horns, JBaJcevellia, etc., these 

 are accompanied by some of the characteristic coal-measure spe- 

 cies such as Spirifer cameratus, Athyris subtilita, Productus 

 semi-reticulatus, etc. On the other hand, the most characteristic 

 fossils of the Zechstein and Copper schists, plants ( Ullmannia, 

 Voltzia, Walchia, etc.), fishes (Acrolepis, Pygopterus) and mol- 

 lusks (Productus horridus, etc.), have so far not been found in 

 North America.' The Trias of the eastern half of North Amer- 

 ica represents the upper member of the European series, the Rhse- 

 tic beds. [This is shown by the plants described by Emmons 

 and Fontaine from North Carolina and Virginia, and those ob- 

 tained from New Jersey and the Connecticut valley by the wri- 

 ter, f] Hence between our coal measures or the so-called Permo- 

 Carboniferous or Permian and our Trias there is a great gap, a hia- 

 tus in our geological history, during which the Permian proper of 

 Europe, at least the Zechstein and Copper schists, were perhaps 

 deposited." 



* M. Fontannes, the Secretary, in a letter to Dr. Frazer, dated Lyons, Jan. 3, 

 1885, says : '• Je viens de lire, avec le plus grand soin, le rapport sur le Congres 

 de Berlin que vous avez eu l'amabilite de m' envoyer. Tous mes remerciments, 

 et en meme temps toutes mes felicitations pour l'exactitude rigoureuse de tous les 

 details. II m'est impossible de comprendre comment, en l'absence de mes notes 

 et de celles des stenographies, vous avez per rediger un travail aussi com- 

 plet." * * * 



f H. B. Geinitz: Dyas (1861-2). H. B. Geinitz: Carbonformation in Neb?-aska, 

 (1866). H. B. Geinitz: Nachtragezur Dyas, 1880-2). Wm. Fontaine : Older Meso- 

 zoic Floras of Virginia ; Monograph. VI., U. S., Geol. Survey. J. S. Newberry: 

 Transactions N. Y. Academy of Sciences, vol. v, p. 18 (October, 1885.) 



