354 A. Vaughan Jennings — Geology of Bad Naulteiin. 



' Spiriferen-sandstein ' is recorded from the borings, but has not beeti 

 mapped as appearing at the surface in the immediate neighbourhood, \ 

 In the concluding section of this paper the rehalionship of these 

 formations will be again referred to, and a possible explanation of 

 their position in the borings suggested. Even if, however, there 

 have been errors of observation in the field, it is probable that the 

 evidence of the borings may be trusted in showing the existence 

 of these formations below the surface. Comparison with other 

 districts would lead one to expect them here, as the usual successioa 

 for North Germany is as follows : — "■''■ 



{A) Upper Devonian | GoSatiLn-kdk'^'' } ^^^^^*- ' -^ 



1 /-Ds-ivfiii T) • i Stringoceplialen-kalk. "■^^■ 



^ ' \ Ca]c-schiefer = ' Orthoceras-schiefer.' 



7 Koblenzer Grauwacken j ^< gpiriferen-sandstein.' 

 ^ (C) Lower Devonian Hunruckschiefer j 1 



. ^ ' 1 iaunus-quarziE. 



\ Taunus-phyllite = ' Sericit-schiefer.' . c\ 



B. The Tertiary Strata. / 



The softer, almost horizontally stratified, beds which form the 

 fertile fields of the Wetterau belong, as already stated, to Oligocene 

 times. In the south-west the whole series of strata is well seen, 

 but at Bad Nauheim itself it is only the upper part that is repre- 

 sented at the surface. In the quarries south of the town and round 

 Ockstadt this portion, however, is typically developed and easily 

 observed. In places there are loosel}^ compacted sands, beautifully 

 colour-banded, and reminding one of those at Alum Bay. Other 

 beds consist of coarse quartz-sand with some ferruginous cement, 

 but infiltrated with calcite, the shining cleavage faces of which 

 often extend over considerable areas. Selenite and chalybite are also 

 commonly present. In the coarser beds the pebbles of older rocks 

 are frequently coated with concentric pellicles of yellow, brown, or 

 brilliantly red iron oxides, and a remarkable ferruginous con- 

 glomerate results. 



In spite of their varied character these strata appear to belong 

 all to the ' Bliittersandstein.' Though unfossiliferous here, they 

 contain at Miinzenberg such mollusca as Litorinella, Cyrena, TJnio, 

 Cyclas, and Helix, as well as leaves of plants such as Cassia, Rosa, 

 Acer, Ficiis, Cinnamomum, Sajnnclus, Amygdalns, and Cratmgns. 



Below the BUittersandstein comes the ' Litorinellen-kalk,' a 

 yellowish limestone with fossils ; again partly of fresli and partly 

 of brackish water habit. Succinea, Pupa, Helix, and Neritina occur 



1 The nearest is a little west of Ober Morlen, where it is said to occur with a dip 

 of 40°-50° S.E. in the same strike line as the Oppersliofen-Krausberg outcrop, 

 where characteristic fossils occur. A patch of schiefer, believed to be equivalent to 

 those of Pfaffenwiesbach containing Orthoceras, is mapped as occurring immediately 

 south of the sandstone. 



2 All these strata are unfossiliferous at Bad Nauheim, but in the Koblenz district 

 contain characteristic types, such as Renssclcrin, 3Iegantcris, Fcntamerus, and 

 Ctenocnnns. In other parts there occur Stromatopova, Calamopora, Fcmstclla, and 

 Chonetes sarcinulata. 



