ss 



THE GEOLOGIST. 



limestones of the Beauee and the Brie. Calcareous debris is rare : and 

 grains of iron and feldspar still more so. On the plateaux the residue of 

 la?vigation is Tery variable, even in the vegetable soil covering the same 

 rocks. Thus on the plateaux above Gurches and Mendon. it rises to 70 

 per cent. : but more to the south, towards Saclay. it is reduced to a few 

 hundredths. In the valleys, also, it varies, not only in the different valleys 

 but also in the longitudinal and in transverse directions. The proportion of 

 fine sand is also very notable in the bottom of the valleys ; on the banks of 

 the Seine and the Marne it varies from a few hundredths. Clay is found also 

 in all the soils round Paris, sometimes pure. Sometimes in the state of marl 

 associated with lime. The soils which cover the plateaux formed by the 

 lacustrine rock of the Beauce and the Brie, are particularly rich in clay. 

 At Crenilly and Tillejuif the proportion of clay is above 50, and it may 

 sometimes reach to 90 per cent. But the clay is especially concentrated 

 in The bottoms of the valleys, whether they be dry or wet. 



The examination of the constituent mineral substances shows that the 

 soil comes in part from the subjacent rocks, and partly from the rocks in 

 the neighbourhood : and that it must not be always regarded as a disaggre- 

 gation in situ, for we often find that in limestone rock the vegetable soil 

 contains not a trace of calcareous matter : and, vice versa, a highly cal- 

 careous soil over a clay base. The vegetable soil M. Delesse considers as 

 decidedly belonging to the " terrain de transport," or drift, as shown by 

 the sand, gravel, and innumerable rolled fragments it contains. 



The practical value of M. Delesse's map is that, in indicating the minera- 

 logical composition of the soil in the Paris district, it is easy to see what 

 lauds should be marled, and which should be drained, and to what extent, 

 and with what materials, manures and extraneous substances should be 

 economically employed in agricultural operations. 



TJeber Tliierjahrfer und Crustaeeenreste in der v.nteren Dyas, oder dem 

 unteren JRothliegenden, der Gegend von Sohen Elbe. Von Dr. H. B. 

 Geinitz. 



On Animal Tracks and Crustacean Remains in the Lower Dyas, or in the 

 Lower Permian Sandstones of the Strata of the Higher JElbe. By Dr. 

 H. B. Geinitz. (Extracted from the 1 Isis ' of Dresden.) 1S62. 



Dr. Geinitz. undismayed by the severe criticism he received at the 

 hands of Sir Roderick Murchlson, {'Geologist.' January. 1861,) proceeds 

 systematically to describe the fossils which are found in his so-called Dyas 

 strata of Central Germany. Mrs. Josephine Ivablik, a lady who cultivates 

 natural science in that neighbourhood, has discovered several interesting 

 fossils, which are described and figured in the work before us. 



The Dalmanites (?) Kall'dw. Geinitz, is figured. It is a small Trilobite, 

 which Geinitz considers may belong to the Silurian genus Dalmanites. Dr. 

 Greinitz also figures a remarkable Phyllopod crustacean, somewhat re- 

 sembling the Branckipns sfaonatis of Linnams. which he considers to be a 

 new genus. Kablikia. The Kablikia Dyadica. Geinitz, is found in the coal- 

 slates of the Lower Dyas, near ^ieder-Stepanitz, on the Higher Elbe. The 

 original specimen is in the Dresden Museum. 



The limestone slates of the Lower Dyas have afforded evidence of . im- 

 pressions, considered by Dr. Geinitz to be those of a Crustacean, the speci- 

 mens of which are also in the Dresden Museum. They are somewhat 

 similar to those which Hall has figured in the ' Palaeontology of Xew York/ 

 considering it doubtful whether they belonged to Crustacea or Fishes. 



The paper is illustrated with two "well-executed lithographic plates. 



