56 



FOSSIL ESTHERI^. 



We may add Gersfeld (see p. 45) as a locality for U. minuta in the Bunter, Haio-er- 

 loch (Hohenzollern), Nimburg (Breisgau), and Weyhers and Fulda (Bavaria), as other 

 localities for U. minuta in the Lettenkohle group, (see p. 44 and p. 45) ; also Durlach 

 (Baden) and Weyhers (Bavaria) as localities for ^. minuta in the Muschelkalk, and 

 Halle (Thuringia) for E. minuta in the Keuper (page 45). 



Table sJiowint^ the occurrence of Estheria minuta in the various memlers of the 



European Trias. 



Members of the Trias. 



England. 



Eastern France. 



Baden, Wiirtemberg, 

 and Bavaria. 



Hanover. 



Thuringia. 



Upper Keuper 

 Lower Keuper 

 Lettenkohle 

 Muschelkalk 

 Upper Bunter 

 Lower Bunter 



* 



* 



Tabingen 



* 

 Durlach 

 Gersfeld 



Elliehausen, &c. 

 Salzgitter 

 Dassel, &c. 



Weimar. 



Johannisthal, &c. 

 Weimar. 



This Table is constructed on imperfect grounds, and therefore is only offered as a pro- 

 visional synopsis. I have not seen specimens from the places the names of which are 

 given in the Table, and which have been referred to as localities for ^& Estheria in certain 

 zones. The asterisks indicate the zones in the several districts from which I have had 

 specimens under examination. ■ - 



Habitat of Estheria minuta. — In Alsace, Baden, Wiirtemberg, Bavaria, Thuringia, 

 and Hanover, the Estheria minuta is associated with Lingula tenuissima, a marine shell, 

 subjected however to the deteriorating influence of fresh water, if the observations on 

 this point at page 48 bear me out. Other marine molluscs also, such as Myacites, Ger-. 

 villia Trigonia or Myophoria, Pecten, and Pleurophorus, accompany E. minuta, at various 

 localities over this wide district, occurring, for the most part, however, in beds amongst 

 which the Estherian shales are occasionally intercalated. The general occurrence of the 

 Estheria in interlaminated shaly beds, strengthens the opinion that they existed chiefly 

 at the intermediate periods when the fresh water had gained some predominance in the 

 shallow seas or lagoons. In the Bunter Sandstone of Alsace, land-plants occlu' in the 

 Estherian clays ; but here, whilst the freshwater Jpus is one of the associates of Estheria, 

 a Limulus intrudes itself in accompanying strata of the same age. (See p. 54). 



In some of the beds of the Keuper, crystals of salt have left their casts abundantly, 

 showing both the saltness and the shallowness of the seas or lakes in which the upper 

 Keuper beds were deposited. But however near to these salt-bearing beds the Estheria 



