Prof. T. Rupert Jones — Fossil Bivalved Entomostraca. 101 



late Mr. A. G. Bain's hypothesis of the Karoo Formation having 

 had a lacustrine origin, or, at least, having been partly formed in 

 fresh or brackish waters. Besides some obscure casts of small 

 Bivalves, Mr. D. Sharpe's Iridince (Trans. Geol. Soc. ser. 2, vol. vii. 

 p. 188, and p. 277) are the only known shells from the Karoo beds. 

 For remarks on the geological characters of this formation, which is 

 either of latest Palaeozoic (Permian) or earliest Mesozoic (Triassic) 

 age, see Quart. Journ. Geol. Soc. vol. xxiii. p. 277 ; and vol. xxxi. 

 p. 529, etc. 



The form most nearly approaching Estheria Greyii in outline is 

 E. rimosa, Goldenberg, Fauna Saraspont. foss., Heft ii. 1877, p. 44, 

 pi. 2, fig, 16-18, from the Carboniferous beds of Saarbruck. 



II. Carboniferous Estheria. 



1. Estheria Daiosoni, Jones. Plate III. Fig, 2. 



In the Geol. Mag. Vol, VII. 1870, p. 220, PL IX. Fig. 15, we ' 

 gave a drawing and brief description of a Nova-Scotian specimen of 

 Estheria Daiosoni,^ already noted and roughly figured by Dr. Dawson, 

 F.R.S., in his Acadian Geology, 1868, p. 256, fig. 78c?. 



Thanks to Mr. Eobert Etheridge, junior, F.G.S., we have now 

 seen better specimens, though still only casts, of this species from 

 Scotland.^ These, collected by the Geological Surveyors of Scotland, 

 and marked "B 1374 E " in the Museum at Edinburgh, are single 

 and double valves, more or less flattened, scattered on the bed-planes 

 of purplish, fine-grained, micaceous shale, in the Lowest Carboni- 

 ferous series, east of Belhaven Bay, near Dunbar. 



These Scotch specimens of E. Dawsoni give more perfect outlines 

 than those previously figured. The subquadrangular shape, wide 

 ridges (11 or 12), short anterior and long posterior moieties of the 

 valves, and the sharp postero-dorsal angle, making the posterior 

 margins somewhat sigmoidal, are characters in this species. No 

 ornamentation is seen either on the casts or the impressions. Fig. 

 2a, right valve ; Fig. 2b, left valve ; internal casts. Magnified 10 

 diameters. 



2. My friend, E. W. Binney, F.R.S., has communicated some 

 specimens of Esthe7-ia tenella from Ciudad Eeal, Spain. In the 

 Neues Jahrbuch fiir Min., etc., 1864, p, 656, E. tenella is quoted 

 from Saarbrticken by Dr, E. Weiss ; and in the vol. for 1869, p. 61, 

 Geinitz mentions it as having been found in shale at Kargalinsk, 

 Russia. He refers these and the Saarbriicken specimens to the Lower 

 Dyadic (Permian) series. 



3. Goldenberg, in his "Fauna Sareepontanse fossilis," ^ part 2, 

 1877, plate 2, figs. 9-18, illustrates Estheria tenella (Jordan), figs. 

 9-11: E. limbata, Gold., figs. 12-15; and E. rimosa, Gold., figs. 

 16-18; together with some Leaice, etc. 



1 Estheria Adamsii and E. Peachii were figured and described on the same occa- 

 sion, loc. cit. PL IX. Figs. 1 and 17. E. punctatella had been already added to the 

 list of Carboniferous Estherim, in the Trans. Geol. Soc. Glasgow, 1865, pi. i. fig. 3, 



2 Geol. Mag. Series II, Vol. III. p. 576. 



3 "Die fossilen Thiere aus der Steinkohlenformation von Saarbriicken," Heft ii. 



