148 PEOCEEDINGS OF THE GEOLOGICAL SOCIETY. [Dec. 17, 



freshwater condition of the waters of the Upper Triassic period for 

 the horizon and localities in which they occur. 



E. minuta, var. Brodieana, is closely related to its type, but is 

 uniformly of less size, has a relatively smaller reticulation, and is 

 only found in the next succeeding group of strata above the Keuper, 

 namely the Bhaetic*, formerly known as the Lower Lias shales, 

 including the Bone-bed. Sections of these beds at Aust Passage, 

 Wainlode, and Westbury, on the Severn, have been published by 

 Strickland, Brodie, and Wright ; and Mr. Etheridge, E.G.S., has 

 supplied me with an accurately measured section of the Garden Cliff, 

 Westbury, in which the exact position of the Estheria-bed and its 

 relation to the immediately underlying marine limestone are care- 

 fully attended to (see Monograph, p. 70). Sections of the same 

 series in Warwickshire (Binton and Wilmcote) have been made and 

 published by Mr. Kirkshaw, E.G.S., and Dr. Wright, E.G.S. Near 

 Erome in Somersetshire, Mr. Charles Moore, E.G.S. , has recognized 

 the Bhaetic group containing this Esiheria ; and he has found these 

 strata near Ilminster and elsewhere. 



In the north, the Bhaetic beds are represented by the fossiliferous 

 shales of Linksfield, near Elgin, long ago referred by the late Dr. 

 Malcolmson and Mr. Patrick Duff t to the Purbeck or Wealden 

 series ; afterwards to the Lower Oolite by Professor Morris ; and 

 lastly to the Bhaetic group by Mr. Charles Moore. 



At Linksfield E. minuta, var. Brodieana, is of somewhat larger 

 growth than is usual with the Bhaetic specimens of Somerset and 

 Gloucestershire; and its reticulation is slightly modified, having 

 sometimes a more linear arrangement of the meshes. It occurs here 

 in company with hosts of Cypridw, that are referable to one species 

 only, as far as I can see, and that is very close to some of the fossil 

 and recent freshwater Candonce. As Mr. P. Duff referred to it some 

 years since as Cyjpvis globosa, I retain the trivial name for this 

 Candona. The so-called Mytilus and other shells of the Linksfield 

 shales do not occur in the Estherian marls. 



Habitat of E. minuta, var. Brodieana. — In Gloucestershire, Wor- 

 cestershire, and Warwickshire, the Bhaetic Estheria occurs along a 

 certain zone immediately above a stratum full of marine shells, 

 which, like others belonging to this Bhaetic stage, appear to be 

 dwarfed, as if they had been the inhabitants of an unfavourable 

 locality, or lived in sea-water under the influence of large freshwater 

 affluents. In the Estheria-bed itself no marine shells are found. 

 Fragments of terrestrial Plants and of Insects in the associated beds 

 indicate the near proximity of the land to the waters in which these 

 deposits were formed. Here, as in the Keuper, we may suppose 

 that the Estlieriai nourished in brackish, if not in fresh, water, at 

 intervals when the saltness of the sea (or lakes) was more or less 

 reduced by the land-waters. 



* Grouped by Herr Gumbel in the Upper Keuper, in his ' Geogn. Beschreib. 

 bayer. Alpengeb.,' a work which I have only lately seen. — March 28, 1863, T.B..J. 



f The death of this esteemed geologist, who worked so long and so well at 

 the geology of Moray, took place during the printing of iny ' Monograph,' after 

 I had received his friendly assistance both by specimens and letters. 



