RECENT ADVANCES IN SCIENCE 227 



which he illustrated the very great variety of leaf-form in 

 the living plant, comparing it with a fossil so-called species, 

 and concluding that a revision of the fossil species is necessary. 



Several important papers on Fuel, notably two parts con- 

 tinuing J. J. Stevenson's invaluable critical survey, " Inter- 

 relations of the Fossil Fuels," pt. ii. on the Cretaceous coals, and 

 pt. hi. on the Jurassic and Triassic coals, have appeared this 

 year (Proc. Amer. Phil. Soc. vols. lvi. and lvii.). In these 

 surveys Stevenson dealt with the whole world, most usefully 

 summarising and critically examining evidence drawn from 

 the immense scattered literature on the subject. 



Zalessky concealed in Russian, without any abstract, a 

 paper entitled " Sur le sapropelite marin de l'age silurien, 

 forme d'une algue cyanophycee," which, from its title and the 

 illustrations, must be of exceptional interest. Hitherto Eng- 

 lish, French, German, or Latin resumes, at least, have been 

 obligatory on those producing scientific work published in 

 such a language as Russian. A paper like this raises the 

 question whether the facts are published at all in an inter- 

 national sense. 



Conacher, in "A Study of Oil Shales and Torbanites " 

 {Trans. Geol. Soc. Glasgow, vol. xvi. pt. ii.), published a most 

 useful and well-balanced account of the oil shales, a difficult 

 subject on which far too much is written by people who do not 

 know what they are talking about. Conacher rightly insisted 

 on certain fundamental similarities between coal and oil 

 shales of some types. Critically considering previous views 

 on the subject, he specified " Resin " as being the principal 

 oil-yielding ingredient, and thinks that animal matter has 

 played no appreciable or essential part in giving to oil shales 

 or torbanites their valuable properties. 



Of shorter papers, Thiessen's conclusion that the spore- 

 exines have stratigraphic value in coal seams was given in 

 abstract in Science, May 10 ; and Jeffrey (Proc. Nat. Acad. 

 Sci. vol. iii.) came to various heterodox conclusions about 

 coals. 



Fischer (Stahl u. Eisen, vol. xxxvii.) gave an important 

 survey of the present position of coal research. 



Stratigraphic Paleobotany, — Devonian plants were added 

 to by Johnson (Sci. Proc. Roy. Dublin Soc. vol. xv.), who 

 described some Pteridosperms from Ireland. 



