2 3 o SCIENCE PROGRESS 



Palaeozoic and Mesozoic epochs {Geol. Foren. Stockholm Forhandl. 

 pp. 212-19) in a work criticising the too ready acceptance of 

 the existence or absence of growth rings in petrified woods 

 as an indication of a seasonal or a uniform climate. He pointed 

 out that by analogy with some of the living types the failure 

 of growth zones is no certain proof that the climate was uniform. 

 The whole subject is one which wants critical and detailed 

 observation, and is of general interest because the climates 

 of the past epochs have been involved in discussions of the 

 position of the poles, the existence of glacial epochs, and other 

 general geological theories. 



One of the three or four notable products of the year was 

 that on Fuels of various ages and types which were dealt 

 with in a most valuable memoir by Stevenson (" Interrelations 

 of the Fossil Fuels," Proc.Amer.Philos.Soc. vol.lv. pp. 21-203). 

 Peats and Tertiary coals received principal consideration in this 

 first part of the work, which surveyed the subject from many 

 points of view and brought together an immense mass of 

 evidence about the various plants forming the fuel-deposits, 

 their mode of deposition and other subjects. This work showed 

 the fallacy of the generally accepted conclusion that true peat 

 is confined to the temperate zones. Any plant, apparently, 

 can, under suitable conditions, become a peat-maker — " the 

 hyacinth, introduced into Florida, where it threatened to ruin 

 the navigable rivers, has become a peat-producer of no little 

 importance." Stevenson gave useful accounts of the coals of 

 the Tertiary of all parts of the world, everywhere linking what 

 he had to say with whatever palaeobotanical evidence his wide 

 research made available. 



Stratigraphic Paleobotany. — In this connection the out- 

 standing features of the year were the discoveries in the 

 Devonian, an epoch of surpassing interest but about which 

 there is usually little to say. Dr. Halle, in his paper on 

 " Lower Devonian Plants from Roragen in Norway " {K. 

 Svensk. Vetenskap Handl. vol. lvii. pp. 1-46, 4 pis.) broke new 

 ground. In his own words, " The important point is that 

 this flora is a very good representative of the type of land- 

 vegetation characteristic of the Lower Devonian, as contrasted 

 with the well-known floras of Kiltorkan, Bear Island, etc., 

 which belong to the Upper Devonian. We are dealing here 

 with the remains of the very oldest land-flora at present known ; 



