424 SKETCH OF PALEOBOTANT. 



shall have been completed. This is specially to be regretted, as so 

 littleihad been done down to 1850 to develop the paleobotanical resources 

 of America. It is also true that at that date little had been done beyond 

 the collection and accumulation of data for study. From the time when 

 the practice of discussing imaginary problems Y/ithoufc any data fell into 

 disrepute the opposite and far more healthful tendency to treat facts as 

 the end of research chiefly prevailed, until at length, at the time when 

 we are compelled to close our record, a sufliciently large body of facts 

 had been brought to light, and, through the organizing power of linger, 

 Brongniart, and Goppert, had been arranged for study and comparison, 

 to render it somewhat profitable to speculate upon their probable 

 meaning. 



In the decade that followed some such speculation was indulged in 

 very cautiously, but this always resulted in the clearer recognition of 

 the need of still more facts, and undoubtedly tended strongly to stimu- 

 late research. Then commenced that systematic attack along the 

 whole line of paleobotanical investigation. Ettingshausen's system of 

 nervation for the determination of dicotyledonous leaves maybe re- 

 garded as the result of the pressure, then irresistible, for the means of 

 identifying the now vast accumulations of this important class of fos- 

 sils. Heer's researches into the fossil floras of Switzerland and of the 

 arctic regions, and Lesquereux and Newberry's investigations into the 

 Dakota, Laramie, and Green Eiver groups of the Western United 

 States, together with Saporta's "Etudes" in the south of Prance, fur- 

 nished more data than that of all the collections previously made from 

 the later formations. 



The work of exploration still goes on. Saporta has elaborated the 

 Jurassic of France, Grand' Eury and Eenault have thoroughly studied 

 the Carboniferous of that country, as have Williamson and Carruthers 

 that of England. Nathorst has opened up the subterranean floral treas- 

 ures of Sweden, and Dawson those of British America, while Engelhardt, 

 Hosius, Van der Marck, and Schenck have continued to investigate, 

 without exhausting, the rich plant-beds of Germany. In America ac- 

 tivity has not diminished, notwithstanding the advanced age of both 

 the principal cultivators of this science. Large works, which have re- 

 quired years in preparation in the hands of both Lesquereux and New- 

 berry, are either on the eve of publication or are far advanced toward 

 comi)letion. Professor Fontaine, of the University of Virginia, has an 

 important work on the Ebetic flora of Virginia in press, and is collect- 

 ing some most interesting material for a second from the lower Creta- 

 ceous or upper Jurassic of the same State. Large collections have 

 lately been made by different parties of the United States Geological 

 Survey, which are now in hand for examination, while fresh material 

 is daily arriving at the National Museum from all parts of the country. 



Between eight and nine thousand species (as species are made) of 

 fossil plants are now known to science, and the time must be near at 



