48 FOSSIL ESTHERS. 



At p. 202, Von Alberti mentions the occurrence of Posidonia minuta in red standstone (Bunter 

 Sandstein), together with Plant-remains, near Sulzbad (Bas-Rhin), and Corcelles (Haute Saone) ; also 

 Lingula tenuissima at Sulzbad and Douptail. (These and other fossils, many undetermined and unde- 

 terminable, were seen by Alberti in the Museum of Strasburg, in 1831.) 



At p. 320, it is stated that Psammodus Elytra, Avicula subcostata, Posidonia minuta, and Equise- 

 tum arenaceum occur both in the Bunter Sandstone 1 and in the Keuper. 



1S34-40. In A. Goldfuss's 'Petrefacta Germanise/ Zweiter Theil. (1834-40), p. 118, 

 the following occurs : 



" Posidonia minuta, nobis, PI. 113, fig. 5. Posidonia testa minuta, transversim ovato- 

 rotunda, plana, inauriculata, costis majoribus concentricis (8-10) minoribusque marginali- 

 bus confertis. Zieten, /. c, pi. 54, fig. 5. These small shells occur bed-like in the 

 Keuper, especially at Hassfurth 2 (not far from Schweinfurth), 3 near Heilbronn, 4 and at 

 Pforzheim. 5 Usually there is only the impression of the outer surface, rarely the remains of 

 the extremely thin shell. The shell is flat, obliquely roundish oval, and has 8-10 convex, 

 regular, concentric wrinkles. In the lower third these become smaller, and lie closer 

 together. There are no ear-like processes." 



1843. In giving an account of the Triassic beds of Wiirtemberg, 1843 (' Das Flozge- 

 birge Wiirtemberg's/ 6 p. 541, &c), P. A. Quenstedt separates the Lettenkohle-group from 

 the lower part of the Keuper, and ranks it as the upper member of the Muschelkalk. 

 Hence some authors refer to Estheria minuta as belonging to the Keuper, after 

 Alberti's classification ; whilst others speak of it as being lower in the scale, either as 

 occurring in the Upper Muschelkalk or between that and the Keuper, according to their 

 views as to the relations of the Lettenkohle for this is regarded by some as being 

 distinct from both the Upper Muschelkalk and the Keuper. Quenstedt's classification is 

 shown in the following table : 



that in the Gres Bigarre, of Sulzbad, there is a Lingula three fourths of an inch long, and three eighths 

 wide ; that in the hard, dark-grey shale of the Wellenkalk of Horger, Wiirtemberg, there is a Lingula half 

 an inch long, and three eighths wide ; that in the dolomitic marlstone of the Lettenkohle of Durlach, 

 Baden, the Lingula are one fourth of an inch long ; and lastly, that in the Estherian marlstone, near 

 Heilbronn, the Lingulce are only three sixteenths of an inch in length. This gradu.il dwarfing of the 

 Lingulce (in the ratio of six, four, two, and one a half), as we rise in the series towards the Keuper, indi- 

 cates the gradually increasing influence of some agency unfavorable to the growth of these Brachiopods, 

 such, perhaps, as a larger and larger influx of fresh water into their habitat, until the water became 

 sufficiently free from salt to allow of the presence of Estherim, whilst the Lingula tenuissima still survived. 



1 P. minuta is not mentioned amongst the fossils of the German Bunter Sandstone, at p. 39, but it 

 is at p. 202, as found at Sulzbad. 



2 In Bavaria, on the River Main, thirty-four miles north-east of Wurzburg. 



3 In Bavaria, on the right bank of the River Main, twenty-four miles north-north-east of Wurzburg. 



* In Wiirtemberg, on the River Neckar, twenty-miles north of Stuttgart, twenty-six miles south-east 

 of Heidelberg. 



5 In Baden, at the confluence of the Enz and the Nagold, fifteen miles south-east of Carlsruhe. 



6 Tubingen, 8vo, 1843. 



