Rev. A. Irving — The Permian Trias Question. 327 



DYAS. 

 A. Zechstein Formatio77. 

 a) Oberer Zechstein (Upper Mao^nesian Limestone). 



B. Rothliegendes. 

 (partly littoral and eruptive, 

 parallel formation of the 

 marine Zeckstein.) 



B. a. Oher Rothliegendes. 

 1 the neighbourhood of 

 Dresden still overlaid by 

 the " Porphyry" of Ham- 

 ichen, and in Saxony ge- 

 nerally by the Flatten - 

 dolomit. 



1). Flaltendolomit Dolomitscher Kalkschiefer, Stink 



kalk, Stinkstein. (Upper Yellow Limestone, 



Conglobated Limestone of North of England, red 



and variegated, dolomite-bearing marls and shales 



in North- West of England.) 

 b). Mittler Zechstein (Middle Magnesian Limestone). ^ 

 2). Rauchivacke or Dolomit. Eauchkalk, Hohlenkalk, 



EifF-Zechstein, partly breccia and ash, interpolated 



■with gypsum, anhydrite, saliferous clay, rock-salt 



beds or ironstone. (Concretionary- and Shell- 

 Limestone, or Crystalline- and Fossiliferous-Lime- 



stone in England.) 

 c) . Unterer Zechstein (Lower Magnesian Limestone) . 

 3). Zechstein, passing downwards into the Dachflotz 



and bituminous Mergelschiefer (Compact limestone 



in England.) 

 4). Kiipferschiefer Bituminous mergelschiefer {Marl- 

 slates in England). 

 5). WeissliegendesiGirAvMegendies) ITllmanniaSandstem 



(Ludwig) with interstratified cupriferous shales in 



Hesse, Mutterflotz or Sanderz in Thiiringen, and 



an older dolomite near Gera. (Not known in 



England.) 



B. b. TTnteres Rothliegendes ( ^ff?c/iia-sandstein of Ludwig) 

 with red and variegated shales and sandstones, feeble layers of limestone and coal, 

 combustible shales, etc., with various eruptive rocks interpolated, especially felsite- 

 porphyry and pitchstone, melaphjTe or basaltite with its green and brown mandelstein, 

 commencing at the base with the region of the grey conglomerates. [In a recent 

 letter the Dresden Professor has pointed out to me that in the contemporaneous 

 igneous rocks of the Lower Eothliegendes we must recognize ' ' three stages, an 

 anteporphyritic, a porphyritic, and a post-porphyritic stage.] 



Nomenclature (after Geinitz) : 



Zechstein : from ' Zeche ' (Zunft) a company or corporation, name given from the 

 numerous huts or houses (Zechenhauser or company's houses) erected upon this 

 formation in connection with the works for obtaining copper-ore from the Kupfer- 

 schiefer and "Weissliegendes. The word ' Zeche ' also means a mine, and so that 

 Zechstein may = mine-rock (Geinitz points out that the same is equally applicable to 

 the formation in Durham and Northumberland, since the coal-pits are siink first 

 through the Magnesian Limestone in that locality). 



liothliegende (or Todtliegende) named from the prevalent red colour and from the 

 general absence of metallic ores in the strata : 2000 feet thick in Saxony and in 

 Thuringia ; freshwater and partly volcanic in origin ; has more local character than 

 the marine deposits of the Dyas. 



= Lower New Eed Sandstone (gres rouge). 



Omalius D'Halloy (1808) included Dyas and Trias under name of "Formation du 

 gres rouge'''' ; later terrain peneen.'" 



One more word in conclusion, and that to enter a gentle protest 

 against the importation of personal sentiment into the discussion of 

 this question, as has been sometimes done during the past two 

 years. The true scientific spirit must seek for truth before all 

 things, even if in the pursuit of it a harsh brush is given occasionally 

 to our personal feelings. No one can look at the vast amount of 

 work which the illustrious Murchison left behind him without a 

 feeling of admiration ; in fact his enormous and indomitable energy 

 had its weak side, as it did not allow him perhaps always to wait 



