514 HISTORY OF GEOLOGY. 



which we have thus introduced, indicating groups which, by evidence 

 of all kinds, of their materials, their position, and their organic con- 

 tents, 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 

 mineralogies] 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 enlightened 

 of them, never employed the characters derived 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 Hum- 

 boldt expresses doubts which perhaps many other geologists do not 

 feel when, in 1823, he says, "Are we justified in concluding that all 

 formations are characterized by particular species? that the fossil- 

 shells of the chalk, the muschelkalk, the Jura limestone, and the 

 Alpine limestone, are all different ? I think this would be pushing the 

 induction much too far." 12 In Prof. Jamieson's Geognosy, which may 

 be taken as a representation of the Wernerian doctrines, organic fossils 

 are in no instance referred to as characters of formations or strata. 

 After the curious and important evidence, contained in organic fossils, 

 which had been brought into view by the labors of Italian, English, 

 and German writers, the promulgation of a system of Descriptive 

 Geology, in which all this evidence was neglected, cannot be con- 

 sidered otherwise than as a retrograde step in science. 



Werner maintained the aqueous deposition of all strata above the 

 primitive rocks ; even of those trap rocks, to which, from their resem- 

 blance to lava and other phenomena, Raspe, Arduino, and others, had 

 already assigned a volcanic origin. The fierce and long controversy 

 between the Vulcanists and Ne'ptunists, which this dogma excited, does 

 not belong to this part of our history ; but the discovery of veins of 

 granite penetrating the superincumbent slate, to which the controversy 

 led, was an important event in descriptive geology. 'Hutton, the 



12 Gisscment dts Roches, p. 41 



