372 HISTORY OF GEOLOGY AND PAL/EONTOLOGY. 



course of countless generations, but at definite periods of 

 creation, by means of a more or less complete re-modelling of 

 the previously existing species in the plant and animal 

 kingdoms. 



The numerous, and in some cases beautifully illustrated, 

 works of Abramo Massalongo (between 1850 and 1861) 

 elucidate the Tertiary floras of upper and middle Italy. 

 Another voluminous writer on Tertiary floras was Baron von 

 Ettingshausen. 1 His first works discuss the Tertiary plants 

 of the Vienna basin and the fossil Proteaceae. 



A method of securing a natural impression of leaves was 

 about this time discovered in the Government Printing Office 

 at Vienna, and Ettingshausen immediately had the method 

 adapted to facilitate scientific researches of recent and fossil 

 types of venation. In a memoir published in 1854, 

 Ettingshausen showed the importance of leaf-venation for the 

 systematic identification of isolated fossil leaves, and suggested 

 a special terminology for the nervation of leaves. His large 

 work is a handsomely-prepared account of Austrian plants in 

 six volumes, Physio typia Plantarum Austriacarum, illustrated 

 by natural impressions of the leaves. Pokorny collaborated 

 with Ettingshausen in the preparation of this work, which was 

 exhibited at the Paris Exhibition in the year 1867. Several 

 independent monographs by Ettingshausen succeeded this 

 work, and methods which he initiated have added very greatly 

 to the security with which fossil leaves may be identified. 

 Ettingshausen followed Heer in constantly making a com- 

 parison between recent and fossil forms, but, unlike Heer, he 

 was an enthusiastic believer in the Darwinian theory of 

 descent. 



Meanwhile the knowledge of Carboniferous floras was being 

 from time to time enriched. W. C. Williamson contributed 

 several works (1851-68) on the Carboniferous flora of Great 

 Britain ; that of North America was being carefully examined 

 by Sir William Dawson and Leo Lesquereux. 



The first complete enumeration of palaeophytological material 



1 Constantin Freiherr von Ettingshausen, born 1862 in Vienna, the son 

 of the physicist, Andreas von Ettingshausen, studied in Kremsmiinster and 

 Vienna ; worked as a voluntary assistant on the Imperial Geological 

 Survey; in 1854 was chosen Professor at the Emperor Joseph Academy, 

 and in 1871 Professor of Botany at Graz University ; he died at Graz 

 in 1897. 



