36 HISTORY OF GEOLOGY AND PALEONTOLOGY. 



The chief merit of Lehmann is his accurate description of 

 the stratified rocks (Flolzgebirge). He distinguished thirty 

 successive bands of rock in the stratified system of Ilfeld and 

 Mansfeld, and set forth the geological structure of that district 

 in an accompanying series of diagrams and sections. Many of 

 the terms in his description of the Thuringian deposits were 

 adopted by him from the miners, andTKave been retained in 

 geological literature; for example, Zechstein or mine-stone, 

 corresponding to the Magnesian Limestone and shales or 

 Upper Dyassic group in England; and rothes Todtliegendes 

 (Rothliegende) or red underlyer, the unproductive basement beds 

 below the ore-bearing, and the equivalent of the Lower Dyassic. 



What Lehmann accomplished for the Permian rocks of 

 Thuringia was accomplished by one of his contemporaries, Dr. 

 Fiichsel, 1 for the Triassic series in the same district. In his 

 Latin work, Fiichsel defined for the first time the scientific 

 use of the terms Stratum (Schicht), Situs (Lager), and Series 

 montana (Formation). He used the term "formation" to 

 signify a succession of strata, which have been formed imme- 

 diately after one another under similar conditions, and represent 

 one epoch in the history of the earth; and this is the signifi- 

 cance which has -continued to be attached to the term in 

 geology. 



Fiichsel recognised nine formations in Thuringia from the 

 oldest or fundamental rocks to the Muschelkalk : 



9. Muschelkalk, or Upper Limestone series (Middle Trias 

 of later authors) ; 



8. The Sandstone series (now Bunter sandstones or Lower 

 Trias); 



7, Granular Limestone and dolomitic marls (now Zechstetn 

 dolomite) ; 



6. The Metalliferous series (Zechstein) and copper slate 

 (Kupfers chief er) ; 



5. White rocks, with interbedded sand and clay; 



4. Red rocks, with interbedded red marble ; 



1 G. Christian Fiichsel (1722-73) studied in Jena and Leipzig, took the 

 degree of Doctor at Erfurt, and passed the great portion of his life as a 

 physician in Rudolstadt. The results of his investigations are published in 

 two works; the chief work appeared at Erfurt in 1762: " Historia terrre 

 et maris ex historia Thuringiae permontium descriptionem erecta" (Ada 

 Acad. elect. Moguntince). The second work was published independently, 

 and is now very scarce, Entwurfznr dltesten Erd ttnd Menschen Geschichte, 

 1773- 



