RECENT ADVANCES IN SCIENCE 231 



and it may be stated at once that there is a far greater differ- 

 ence between this flora and that of the Upper Devonian than 

 between the latter and the Lower Carboniferous." The beds 

 in which the relatively well-preserved fossil impressions were 

 found was probably a fresh-water deposit, the contained plants 

 having travelled no great distance. In addition to new species 

 Halle gave most useful descriptions of species he identified 

 with Dawson's original Arthrostigma gracile and Psilophyton 

 princeps. Perhaps no genus has been more abused by uncritical 

 and insufficiently experienced pakeobotanists than Dawson's 

 Psilophyton, and so Halle's remarks were most useful and timely. 

 As throughout the strata older than the Tertiary the very 

 existence of the Bryales is doubtful, particular interest attached 

 to numbers of well-preserved, stalked sporogonia containing 

 spores, which were remarkably moss-like in appearance. 



In Scotland also peculiar Devonian plants came to light, 

 and at the meeting of the British Association at Newcastle a 

 committee presented its report on the Plant-bearing Cherts 

 at Rhynie, Aberdeenshire {Rep. Brit. Assoc. Sci. 191 6, pp. 206- 

 16), the plants of which were reported on by Kidston. The 

 plants were petrified in masses in a chert about 8 ft. thick of 

 Old Red Sandstone age. The chert represented the infil- 

 tration of an ancient peat bed by silica. The peat appeared 

 to have been formed entirely of two plants, the more crowded 

 and numerous (Rhynia) composed of rootless rhizomes with 

 tapering aerial stems bearing cylindrical sporangia but no 

 leaves . 



Work on the Carboniferous was remarkably scanty in 

 191 6. Arber gave a comprehensive account of the fossil flora 

 of S. Staffordshire (Phil. Trans. Roy. Soc. Lond. B, vol. ccviii. 

 pp. 127-55, pis. II. -IV.), separating the floras of the red-grey 

 Unproductives and the grey Productives. Useful and exhaus- 

 tive lists of localities were given, and several forms well 

 illustrated. A new " genus " was created for the external 

 surfaces of calamite impressions, but as it covered almost the 

 same ground as Grand' Eury's old term Calamodendrofloyos , its 

 creation would be difficult to justify. The conclusion of the 

 paper supported Kidston's view that the whole productive 

 coal measures of S. Staffordshire belong to the Middle coal 

 measures. 



Two new foliage impressions from the Trias of Pennsyl- 



