JEFFREY. — NATURE OF SOME SUPPOSED ALGAL COALS. 287 



afforded by the extreme hypotheses which this interpretation demands. 

 For example, M. Bertrand in his work cited above ^® states that the oil- 

 shale of New South Wales, forming a layer fifteen feet in thickness, 

 composed practically entirely of the organisms known as lieinschia 

 australis, must have been laid down a single season during a period of 

 low water. He makes similar statements in regard to the thick 

 bituminous deposits of Autun. It is inconceivable that such a huge 

 mass of algal matter, which in its fresh condition must have been 

 enormously greater in volume, should have been accumulated and 

 synchronously preserved in so short a time. The problem of the 

 preservation of this great amount of gelosic substance is not rendered 

 easier by the supposition that the antiseptic was bituminous in its 

 character and consequently must have been poorly soluble or quite 

 insoluble in w^ater. It is easy to imagine the preservation of logs and 

 even of the harder parts of animals in asphaltic lakes, such as have 

 been found in California, South America and certain of the West 

 Indian Islands ; but the best developed scientific imagination would find 

 it difficult to picture enormous masses of gelatinous matter, impreg- 

 nated rapidly and completely by preservatives of a bituminous nature. 

 It moreover seems clear that the intervention of bituminous matter 

 in the process of the formation of such coals from gelatinous Algae 

 is absolutely essential, for as Bertrand has pointed out, the contraction 

 in the organisms constituting boghead coals although great (from 1/7 

 to 1/24 in volume), would only correspond to a proportion of gelatinous 

 substance from 105 to 360 per milk; whereas the amount of gelatin in 

 ordinary dry commercial gelatin is from 700 to 800 per mille. He con- 

 cluded that the deficiency must be made up by the infiltrated bitumi- 

 nous matter. 



Further, even if it be granted that bituminous matter actually enters 

 into the transformation of gelatinous Algae into boghead coals as the 

 hypothesis originated and elaborated by Renault, Bertrand and Potonie 

 demands, the question of the origin of this substance in connection 

 with large accumulations of Algae in widely separated parts of the 

 world and at remote geological epochs constitutes a very grave 

 difficulty. It has been variously suggested that the bituminous sub- 

 stance originates from the remains of animals or from a transformation 

 of a part of the algal substance itself into bituminous matter. In view 

 of the relatively insignificant amount of animal matter compared with 

 vegetable matter on the surface of the world at the present time we are 

 scarcely justified in drawing the inference that the remains of animals 



^^ Charbons Humiques et Charbons de Purins, p. 2. 



