130 STEVENSON— INTERRELATIONS OF THE FOSSIL FUELS. 



This bed underlies 52 meters of sand and gravel; at 5 meters 

 below it is a thin streak of lignite resting on white clay, which con- 

 tains Helix and Planorbis. At Tour-du-Pin, the partings are marly 

 and the underclay contains laminse of lignite, which become thicker 

 as the bed is approached. The lignite there is distinctly laminated 

 and is so hard that it can be removed only with picks. The laminae, 

 completely " bitumenized," show vegetable impressions but no leaves 

 or flattened stems. Near Vion, on the border of Isere, mineral 

 charcoal is abundant between the lamin?e and embedded trunks of 

 trees are not rare. Some parts of this deposit are brown, but others 

 are " bitumenized." The constituents are distinct, for Fournet recog- 

 nized debris of birch, juniper, fir, cherry and walnut, with sedges, 

 rushes, elytra of insects and Planorbis. He was impressed by the 

 remarkable resemblance to coal beds ; the partings, the passage of the 

 floor into the lignite, the lamination and the abundance of mineral 

 charcoal. One cannot fail to see in Fournet's description an equally 

 close resemblance to peat deposits ; land and freshwater mollusks, 

 elytra of insects, all found in the lignite as well as in the underclay, 

 the character of the plants, the structureless mass in which the plant 

 remains and the shells are embedded. 



Daubree^^^ published some notes respecting his observation in the 

 Lower Rhine area. Near Soultz-sous-Forets, he found marls with 

 layers of sand. The latter contain bituminous lenses, which near 

 Bechelbronn have 2 per cent, of bitumen with some pyrite. They 

 hold much carburetted hydrogen and disastrous explosions have oc- 

 curred in the works. Some thin beds of lignite were seen, which 

 have impressions of Helix, Lymncca and Bulimus. The same shells 

 were seen at Lobsann, where, above the marls, are freshwater lime- 

 stones with thin lignites, in all from 5 to 9 meters thick. This hme- 

 stone yields 10 to 18 per cent, of bitumen and contains gypsum as 

 well as pyrite. It is rich in Cliara, the individuals being silicified and 

 remarkably well preserved ; but other remains of vegetables are in 

 poor condition. 



The lignite streaks are very thin and only some millimeters apart, 

 there being alternate layers of lignite and limestone, sometimes 40 



181 Daubree, " Notes sur le gisement du bitume, du lignite et du sel," etc., 

 Bull. Soc. Geol. France, II., Vol. VII., 1850, pp. 444-450. 



