REVIEWS 381 



to be nearly identical in specimens of notably different composition. In 

 general the extinction angle seems to decrease with increasing iron, but the 

 author points out that the composition may vary in a complex way and no 

 very sure conclusions can be drawn. 



A. D. B. 



Ninth Report of the Director of the Science Division. By John M. 

 Clarke. New York State Museum Bull. 164. 1913. Pp. 

 241, pis. 46. 



This publication includes the 66th Report of the State Museum, the 

 3 2d Report of the State Geologist, and the Report of the State Paleon- 

 tologist for 1Q12. Although unaccompanied by descriptions, there are 

 36 plates illustrating the Devonian fossils of Brazil and of the Falkland 

 Islands. A full description of the fauna is to be published by the 

 director of the Geological Service of Brazil. 



The object in printing these plates is to show the distinctive charac- 

 ters of the southern Devonian fauna. Although fundamentally related, 

 it is apparent that the genera of the northern and southern American 

 habitats developed in separate basins with restricted communication. 

 From the fossils there is indication of a continuous strand line from 

 South America through the Falkland Islands to South Africa. 



T. T. Q. 



Stratigraphy and Paleontology of the Alexandrian Series in Illinois 

 and Missouri. Part I. By T. E. Savage. Extract from 

 Bull. 23, Illinois State Geol. Survey. 1913. Pp. 124, pis. 7. 



This part of the subject treats only the Girardeau and Edgewood 

 limestones. Part II on the Essex and the Sexton limestones is in prepara- 

 tion. The report discusses the stratigraphic and paleontological rela- 

 tions of the series. A large part is a description of the fossils. 



Alexandrian series is the name proposed for the early Silurian strata 

 of Illinois and eastern Missouri which occupy a position above the top of 

 the generally accepted Richmond and below the Brassfield (Ohio Clinton) 

 limestone. The series consists of a number of closely related formations; 

 these record a succession of oscillatory northward sea advances separated 

 by breaks in sedimentation due to temporary withdrawals of the sea. 

 The Girardeau was the earliest and the least extensive invasion; the 

 cycle closed with the most widespread, the Sexton Creek submergence. 



T. T. Q. 



