394 



SCIENCE 



[N. S. Vol. XXXIX. No. 1002 



strata and fauna of this faeies not only in 

 Parana, but also in the state of Matto Grosso, 

 Brazil, Bolivia, Argentina and the Falkland 

 Islands. The work hence possesses a wide 

 scope. 



The stratigraphic succession in Parana is as 

 follows, in descending order: Tibagy sand- 

 stone, Ponta Grossa shales, Furnas sandstone. 

 The strata are underlain by an ancient, crys- 

 talline complex, and are overlain by Permo- 

 Carboniferous deposits containing glacial till. 

 A very interesting member of this series is 

 the barren, basal Furnas sandstone, which ap- 

 pears to be paralleled by a similar sandstone 

 situated at the base of the Devonian in 

 Bolivia and Argentina. It overlies, at difPer- 

 ent places, ancient crystallines, Cambrian and 

 Silurian strata, and hence seems to indicate 

 a widespread transgression of the sea in South 

 America at the beginning of Devonian time. 



The austral fauna is believed by Dr. Clarke 

 to be of Lower Devonian age, and is consid- 

 ered by him to have sprung from a boreal 

 Silurian ancestry, owing its peculiarities to 

 its development in isolation in southern 

 waters. 



One of the most notable aspects of the dis- 

 cussion is the fact, brought out with great 

 clearness, that the American austral Devonian 

 fauna iinds its nearest relative in the Bokke- 

 veld fauna of the same age in South Africa. 

 Indeed the species of the Falkland Islands 

 are more closely akin to those of South Africa 

 than they are to those of the state of Parana. 



These relations lead to an interesting re- 

 construction of the lands and continents of 

 Devonian time. The existence of a more or 

 less intimate connection between Africa and 

 South America had been foreshadowed with 

 greater or less clearness by various writers. 

 The author suggests that an Antarctic conti- 

 nent existed at that time, whose strand 

 stretched from South Africa to the Falkland 

 Islands and thence north into Chile and Ar- 

 gentina, along which the austral species 

 migrated. A large island situated near the 

 present state of Parana was separated from 

 the Antarctic continent by a comparatively 

 narrow waterway. 



A northern land mass embraced the northern 

 part of South America and a large area on 

 the site of the present North American con- 

 tinent. A land bridge is believed to have ex- 

 tended across the north Atlantic ocean, unit- 

 ing North America and Europe, its existence 

 being indicated by the close relation of the 

 early Devonian faunas of Maine to those of 

 the Coblentz district on the Rhine. It is 

 thought probable that the center of disper- 

 sion of the austral species was located in cen- 

 tral Africa. The division of the Lower De- 

 vonian faunas into a boreal and austral faeies 

 and their geographic distribution are explained 

 by these facts. 



The larger part of the monograph is devoted 

 to a description and critical discussion of the 

 species constituting the austral Devonian 

 fauna of South America and a consideration 

 of their relations to those of South Africa. 



Illuminating comments are made upon the 

 distinguishing characteristics of the austral 

 types in connection with the discussion of the 

 leading groups, the treatment of the charac- 

 teristics of the trilobites being especially valu- 

 able. 



The work is published iii the English and 

 Spanish languages in parallel columns. Its 

 illustrations are of a high order of excellence. 

 The monograph is a notable contribution to 

 our knowledge of the geology of South Amer- 

 ica and is a credit both to the author and tO' 

 the Geological Survey of Brazil. 



Charles K. Swartz 



Baltimore, Md. 



SPECIAL ARTICLES 



A NEW CYTOLOGICAL STAINING METHOD 



During the course of an investigation on 

 spireme formation and chromosome number in 

 the pollen-mother cells of various species of 

 Lilium and Nicotiana, considerable time was- 

 expended in testing and experimenting with 

 stains and staining processes. In plants such 

 as Nicotiana, where the chromosomes are small 

 and the characteristic number is large (48) 

 (24), it is desirable, especially in certain 

 phases of the maturation phenomena, to have- 

 a stain combination which will differentiate 



