SYSTEMATIC DESCRIPTIVE GEOLOGY. 551 



these primitive rocks, generally highly inclined, 

 rest other transition strata; upon these, lie se- 

 condary ones, which being more nearly horizontal, 

 are called flotz or flat. The term formation, which 

 we have thus introduced, indicating groups which, 

 by evidence of all kinds, of their materials, their 

 position, and their organic contents, are judged to 

 belong to the same period, implies no small amount 

 of theory : yet this term, from this time forth, is to 

 be looked upon as a term of classification solely, so 

 far as classification can be separately attended to. 



Werner's distinctions of strata were for the 

 most part drawn from mineralogical constitution. 

 Doubtless, he could not fail to perceive the great 

 importance of organic fossils. "I was witness," 

 says M. de Humboldt, one of his most philosophical 

 followers, " of the lively satisfaction which he felt 

 when, in 1792, M. De Schlotheim, one of the most 

 distinguished geologists of the school of Freiberg, 

 began to make the relations of fossils to strata the 

 principal object of his studies." But Werner and 

 the disciples of his school, even the most enlight- 

 ened of them, never employed the characters de- 

 rived from organic remains with the same boldness 

 and perseverance as those who had from the first 

 considered them as the leading phenomena: thus 

 M. de Humboldt expresses doubts which perhaps 

 many other geologists do not feel when, in 1823, he 

 says, "Are we justified in concluding that all forma- 

 tions are characterized by particular species? that 



