514 Scientific Intelligence. 



plugs that are rich in the ores of fluorspar, lead, and zinc, the 

 distribution, occurrence, and origin of which are discussed by 

 Currier. The general geography is treated by Salisbury. 



The most interesting portions are those dealing with structural 

 geology (Part II), stratigraphic geology (Part III), and paleon- 

 tology (Part VI), all b}^ Weller and Butts. The Mississippian is 

 divided into a "Lower" series embracing the Kinderhook, Osage, 

 Meramec, and Ste. Genevieve, and an "Upper" for the various 

 members of the Chester, but both are regarded as of one period. 

 The well known differences of opinion between Weller and Ulrich 

 regarding the sequence and correlations of the various Chester 

 members are clearly stated by the former. Only the fossils which 

 are more important stratigraphically are described and figured 

 photographically. c. s. 



3. Devonian Floras, a study of the Origin of Cormophyta; by 

 E. A. Newell Arber, Pp. 100, 47 figs, and portrait. Cam- 

 bridge (University Press) 1921. — It would be manifestly unfair 

 to a friend who has gone to criticise a work left as a first draft by 

 the author. It seems to the reviewer, however, that the ' ' critical 

 review" of Devonian floras is so incomplete as to be of little value 

 as a work of reference, and that it would have been kinder to 

 Arber 's memory to have left at least this part of the work unpub- 

 lished. 



Arber considers that the Devonian floras represent an earlier, 

 which he calls the Psilophyton flora, and a later, which he calls the 

 Archaeopteris flora. Psilophyton itself is regarded as identical 

 with the petrifled remains described as Rhynia, and these along 

 Avith Arthrostigma, Pseudosporochnus, Thursophyton, etc., are 

 considered as Thallophytes which, anatomically, stand half way 

 between existing Thallophyta and vascular plants. These are the 

 Procormophytes and are not reduced Cormophj^tes or in any way 

 related to the existing Psilotales, but represent part of the ances- 

 tral stock of the unrelated phylae Sphenopsida, Pteropsida and 

 Lycopsida, or what I would call the Arthrophyta, Pteridophyta 

 and Lepidophyta. That is to say, the Sphenophyllum-Calamite- 

 Equisetum phylum, the Lepidodendron-Sigillaria-Lycopod phy- 

 lum, and the Fern phylum along with higher derivatives, are of 

 independent origin from an algal ancestry. Arber contends that 

 the modern Psilotales are also of algal origin but at a much later 

 geological period and independently, as also are the Bryophyta. 

 Most botanists will agree to the algal ancestry of the so-called 

 vascular plants as there is really no alternative. That they are 

 as polyphyletic as Arber thought is extremely doubtful, although 

 this is the position taken by Church in his recent speculation on 

 the subject. 



Both Arber and Church are influenced by the tradition of 

 primitive oceans on a cooling globe, which may or may not have 

 been true. In any event it should be remembered that the dura- 

 tion of time since the earth flrst became suitable as an abode for 



