40 HYATT ON THE TERTIARY SPECIES 



No stratification was observed, and consequently it was not possible to determine 

 whether the rocks dipped towards the valley or not. These characteristics indicate 

 a continuous deposition, or rather precipitation of calcareous matter, since it is hardly 

 possible to conceive that any metamorphic changes could have taken place sufficiently 

 extensive to destroy the marks of stratification. It would seem a fact that these 

 rocks must have been deposited under circumstances very similar to those which occurred 

 when the brecciated limestones of the outer rim were formed. 



This is evidently the view taken by Prof. Fraas, since he alludes to them in the following 

 words : " Diesem Griesfels oder den Breccienkalk begegnen wir zum erstenmal bei Steinheim, 

 das von einem solchen Schuttgebriges regelmassig umlagert ist." ^ And again, " Sobald 

 man sich aber dem centralen Klosterberg, und den Dorf nahert, wiederholen sich gleich den 

 Breccien Erscheinungen aus dem Ries : regellose Massen alteren Juras, die in tertiaren 

 Sand und Kalk drin stecken." ^ 



Sandberger ^ describes these rocks under the name of " die klotzigen Kalke," and says, 

 that though no stratification is found by which the superposition of the fossils can 

 be definitely determined, they contain the same association of fossils as in the strata of the 

 Pit, up to the introduction of " Carinifex multiformis." 



The statements with regard to the geology, are entirely in accordance with my own 

 observations, except the portion of Prof. Fraas' remarks which refer to the underlying 

 structures of the Jura. With regard to these, I am not capable of judging between his 

 and Quenstedt's views, nor has the question an important bearing upon the age 

 of the rocks under consideration. Whether the Cloister ridge is an irregular mass, as 

 stated by Fraas' or an anticlinal ridge, as held by Quenstedt, it is, according to both 

 authorities, capped by the tertiary deposits here called the Cloister ridge rocks, and these 

 alone are concerned in the present discussion. When we attempt to compare the fauna of 

 the opposite sides of the valley, we are at once struck by the great differences between the 

 fauna of the Cloister ridge and Burgstall rocks. PI. levis ? PI. °^^'^Su"^, and PI. oxystomus 

 in the rocks of the Burgstall present the characteristic association of forms found in 

 the fauna of the Cloister Pit, formation " m," rather than what their geological position 

 would lead one to expect, though, as has been shown, these species are really the direct 

 descendants of PI. levis, and their occurrence here ought not to surprise any one. On the 

 other hand the rocks of the Upper Tier on the Cloister ridge, though they resemble 

 the Coarse Limestone closely in texture, and may be of the same age, have a very 

 different set of fossils. Pu^ja antiqua, Lymneus socialis, an unknown Helix, the tooth 

 of a rodent ; PI. steinZtlnsis, PI- tenuis, PI. "1^'% and PI. discoideus are all distinct 

 from those of the Coarse Limestone. PI. ""^uvT' alone represents the species of this last 

 named formation. 



The fossils of the Upper Tier are, as remarked by Prof Sandberger, similar to those in 

 the lowest of the Pit deposits. In the next or Lower Tier this likeness to the fauna of the 

 Pits is increased, but the change consists more in the relative proportions of the species 

 than in the introduction of new forms. Lymneus socialis, Gillia utriculosa, PI. tenuis, 

 PI. "'Zl^r, PI. discoideus, are abundant, and PI shMelmensis very rare. The prevail- 

 ing form is, however, as in the Pit formations, PI. discoideus, except in places where 

 Lymneus socialis excludes all other forms. 



1 Op. ciL, p. 13. " Op. cit., p. 14. = 0/. cU., p. 630. 



