A. Vaughan Jennings — Geology of Bad Natihehn. 361 



by the data given by the borings ; (?>) the extent and character 

 of the ancient lake ; (c) the reasons for the clieniical and physical 

 characteristics of the springs ; and {d) the connection between the 

 eruptive rocks and the genei'al phenomena of the district. 



In discussing these points it is scarcely possible in any case to 

 make dogmatic statements, and the following remarks must be 

 regarded only as a statement of the case for investigation. 



(a) When one examines the published details of the different 

 borings one cannot fail to be struck by the wide differences which 

 exist, in so small an area, between the depths at which the 

 Palgeozoic rocks were encountered. 



Fig. 5. — Geological explanation of the data farnislied b/ the borings bare suggested. 

 B. Bljittersandstein. L. Litorinellen-kalk. 



T. Taunus-quarzit. S. Spiriferen-sandstein. 



0. Orthoceras-schiefer. S.k. Stringocephalen-kalk. 



Although the Devonian rocks of the Johannisberg are dipping 

 south-east at a high angle where they disappear below the Tertiary 

 beds, and are met with at 120 m. in boring 4, yet they are not 

 touched at all in borings 5 and 11. The deep boring 2, on the 

 other hand, while it meets Palfeozoic rock at 130 m., does not 

 touch the Taunus-quai'zit, but traverses some 165 m. of * Orthoceras- 

 schiefer ' and terminates in ' Spiriferen-sandstein.' Borings 7 and 

 12, on the other hand, strike the 'Stringocephalen-kalk' immediately 

 below the Tertiaries, and terminate in that formation. 



These facts appear to show that in the first place the old land- 

 sui-face on which the Tertiary beds were deposited has a distinctly 

 irregular contour, and secondly, that by some agency, either folding 

 or faulting, the members of the Middle Devonian series are present 

 under Nauheim at no great depth, but with very limited horizontal 

 extension. 



The explanatory section published in connection with the old 

 geological map, a copy of part of which is given on p. 351, looks 



