246 Proceedings of the Royal Physical Society. 
Dr Hibbert, as far back as 1836 in his classical paper in the 7ransactions of 
the Royal Society of Edinburgh, called attention to the absence of marine 
forms; and from remains of land plants, entomostraca and fish, which occur 
so abundantly in it, he inferred that the limestone was of freshwater origin. 
In 1903 Dr Traquair, as already stated, from the large proportion of the 
fossil fishes common to that limestone and the Dunnet Shale, thought that it 
was probably estuarine. Since the publication of that paper, Dr F. D, 
Falconer obtained additional evidence bearing on the point. The Raw Camps 
or Burdiehouse Limestone is extensively mined in the neighbourhood of 
West Calder, where it contains chert in which Dr Falconer detected the 
Monactinellid sponge spicules of Spongilla. In the same bed with the cherts, 
stigmaria roots are to be seen in the position in which they lived and died, 
thus affording strong presumptive evidence in favour. of Hibbert’s view. 
Moreover, among the fishes obtained from Burdiehouse the dipnous fish 
Uronemus—a true “lung-fish”—is not uncommon in the Hugh Miller 
collection in the Royal Scottish Museum, Edinburgh. 
DEPOSITION OF OIL-SHALES. 
Mr Steuart, in his chapter on the chemistry of the oil-shales in the 
Geological Survey Memoir on “The Oil-Shales of the Lothians ” (Second Edition, 
1912), discusses their nature and origin. He shows that there is little 
bitumen or wax present in them as such, but that these substances are only 
developed by destructive distillation. It is therefore certain that they owe 
their nature to organic matter, but not from the decay of plant or animal 
matter leaving a residue of wax or fat. He further points out that some of 
the oil-shales are largely made up of entomostracan remains, so that he 
concludes that both plants and animals have entered into their composition. 
From conversations with him and a letter just received from him, I find that 
he is also of opinion that the volcanoes which were so active round about the 
oil-shale area, and within it, at several periods during the, accumulation of 
the oil-shales, may have contributed towards their production by supplying 
warm water to the lagoons in which they accumulated, and in providing the 
waters with solutions which prevented the decay of the organic matter, and 
by periodic exhalations which poisoned and killed off the inhabitants of the 
lagoons. 
These conclusions of Mr Steuart seem to me to be well substantiated by 
the study of the area under consideration. The oil-shales seem to have been 
deposited in quiet by-waters of river deltas or lagoons into which only the 
finest of sediment was carried, and that in very limited amount. In these 
waters a seasonal plankton of very lowly plant life appears to have arisen 
