166 REPORT—1905. 
The collection also includes plaster casts of one of the Bootle foot- 
print slabs, and another of sundry prints, not named, and of ELqwiselwm 
Keuperina, which does not in any way resemble the plant impressions 
alluded to in the report. 
Note on the Occurrence and Habitat of Estheria in the Trias of Britain. 
By Tue SEcRETARY, 
The conditions under which the Triassic rocks of Great Britain have 
been laid down have long been a matter of dispute. They have been 
claimed as marine, lacustrine, and fluviatile deposits by various workers, 
but in each case it has been found that serious difficulties stood in the 
way of the acceptance of any one of these methods of accumulation. 
In recent years the idea has been steadily gaining in strength among 
geologists that the action of wind in a desiccated region will best explain 
the peculiar features which the Triassic rocks exhibit. It has never been 
denied that water has played an important part in their deposition, but 
this seems to have been of an inconstant nature, like the temporary streams 
and lakes which appear for a time in the deserts of to-day and then dis- 
appear by evaporation or other causes. 
The problem has almost invariably been approached from the physical 
standpoint, and but little attention has been paid to the paleontological 
side of the question. 
This is doubtless due to the fact that the fossil contents of the Triassic 
rocks are few in number and difficult to understand, features they possess 
in common with the fauna and flora of existing deserts. 
The little Phyllopod crustacean, Hstheria minuta, is by far the most 
common, the most widely distributed, and the most characteristic fossil of 
the Triassic period, and an examination of the beds in which it is found, 
the fossils with which it is associated, and the conditions under which 
its congeners of the present day exist, may help towards a better under- 
standing of the problem stated above. 
We owe most of our knowledge of fossil Estheria to Professor Rupert 
Jones, F.R.S., whose monograph in the Palzontographical Society’s ‘ Pro- 
ceedings’ (1862), and subsequent papers published in the ‘ Geological 
Magazine’ and other journals, have furnished most of the materials for 
this note. 
Only one species, Estheria minuta,! Alberti, has been found in the 
British Trias, and one variety, Estheria minuta, var. Brodieana, formerly 
thought to be limited to the Rheetic. 
With the exception of some specimens found by Mr. C. E. de Rance 
in the Lower Keuper of Alderley Edge, Cheshire, and recorded in last year’s 
report,” all the British specimens of ELstheria minuta have been obtained 
from the Upper Keuper. 
In the European Trias it occurs in the Lower Bunter of Eastern 
France, the Upper Bunter of Baden and Hanover, the Muschelkalk of 
Baden and Thuringia, the Lettenkohle of Eastern France, Baden, 
Hanover and Thuringia, the Lower Keuper of Thuringia, and the Upper 
Keuper of Wiirtemberg and Hanover. 
It ranges, then, through all the members of the Triassic series from top 
' Monog. Pale. Soc., 1862, p. 57, Pt. ii.; Geol. Mag., 1898, p. 292, fig. 3. 
2 B.A. Trias Report, Pt. ii. p. 277 
