1862.] JONES FOSSIL ESTHERICE. 147 



In England E. minuta is abundant in the upper portion of the 

 Keuper of Somersetshire (C. Moore), Worcestershire (Symonds), 

 Warwickshire (Strickland, Murchison, Brodie), Leicestershire (Plant), 

 and Cheshire (Hull) ; and does not appear to have been met with in 

 any other division of the English New Red Sandstone. 



The sources of information and material that have aided me during 

 the last ten years in working up the history of E. minuta are very 

 numerous, and I have gratefully acknowledged the help of my 

 Foreign and English friends — including the veteran Yon Alberti, the 

 late lamented Bronn, and many others, in the ' Monograph ' before 

 referred to. 



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

 Bavaria, Thuringia, and Hanover, Estheria minuta is associated with 

 Lingula tenuissima, a marine shell, which has been subjected appa- 

 rently to the deteriorating influence of fresh water. (See Mono- 

 graph, p. 48.) Other marine mollusks 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 Estherice 

 in interlaminated shaly beds strengthens the opinion that they ex- 

 isted chiefly at the intermediate periods when fresh water had gained 

 some predominance in the shallow seas, lakes, or lagoons. In the 

 Bunter-sandstone of Alsace, land-plants occur in the Estherian clays ; 

 and here, whilst the freshwater Apus is one of the associates of 

 Estheria, a Limulus (?) intrudes itself in accompanying strata of the 

 same age. 



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 Estherice occur, 

 they are never found in them. Such pseudomorphic salt-crystals 

 occur near Liineberg, in the shales with Lingula tenuissima, alter- 

 nating with limestones, just above the Lettenkohle group, in the 

 dolomitic beds of which latter Estheria minuta occurs (sparingly) 

 with Myophorice, &c. 



In England there are no marine organisms (fishes being excluded 

 as doubtful witnesses) accompanying the Estherice of the Keuper; 

 and these might have been at once regarded as of equally freshwater 

 habits with their recent congeners, were it not that the salt condi- 

 tion of the waters depositing much of the Keuper sandstones and 

 shales is proved by the masses of rock-salt and by the casts of the 

 cubical crystals of salt occurring abundantly in some beds all over 

 the country of the Keuper. Still Estherice have not been found (to 

 my knowledge) in these salt-bearing beds. They appear to keep a 

 definite line above the horizon of the rock-salt and beneath that 

 of the salt-pseudomorphs, and may represent a nearly, if not quite, 



and the Avicula contorta (Bone-bed) series and the Dachsteinkalk constituting 

 the Upper Keuper, according to G-umbel. He states also that it occurs in the 

 " Buntsandstein " on both sides of the Alps. — March 28, 1863. 



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