1824.] De la Beche's Selection of Geological Memoirs. 373 



Messrs. Junker and Dufrenoy. Considerations on the Place 

 that the Granite Rocks of Mont Blanc and other central Sum- 

 mits of the Alps ought to occupy in the Order of Anteriority of 

 the primitive Series ; by M. B. de Villiers. Memoir on the 

 Geology of the Environs of Lons-le-Saunier ; by M. Charbaurt. 

 On the relative Positions of the Serpentines (Ophiolites) Dial- 

 lage Rocks (Euphotides), Jasper, &c. in some parts of the 

 Apennines ; by Alex. Brongniart (with lithographic sections, 

 &c.)- On Fossil Vegetables traversing the Beds of the Coal 

 Measures ; by the Same (with a lithographic print of the Coal 

 Mine of Treu'il, near St. Etienne, showing the Stems of large 

 Vegetables). Notice on the Coal Mines of the Basin of the 

 Aveyron; by M. du Bosc. Notice on the Geology of the 

 Western Part of the Palatinate ; by M. de Bonnard. On the 

 Zoological Characters of Formations, with the Applications of 

 these Characters to the Determination of some Rocks of the 

 Chalk Formation ; by A. Brongniart (with a lithographic print 

 of organic remains, and another of the Montagne des Fis). 

 Notice on the Hartz ; by M. de Bonnard. On the Calcareo- 

 trappean Formations of the southern Foot of the Lombard Alps ; 

 by A. Brongniart. Notice on the Magnesite of the Paris Basin, 

 and of the Position of this Rock in other Places ; by the Same 

 (with a plate of sections). Observations on a Sketch of a 

 Geological Map of France, the Pays-Bas, and neighbouring 

 Countries ; by M. d'Omalius d'Halloy (with the map). On the 

 Geology of the Environs of St. Leger sur Dheune (dep. of the 

 Saone and Loire) ; by M. Levallois. 



In his table of Equivalent Formations, Mr. de la Beche has 

 inserted the muschelkalk and quadersandstein of Germany as 

 separate formations, in order to show the opinions at present 

 entertained on the subject by some continental geologists, who 

 consider the muschelkalk as distinct from our lias ; and conceiv- 

 ing it to be of some importance to determine if we are or are not 

 to add two new formations to our secondary rocks, he has, in an 

 Appendix, subjoined to the above memoirs, the description of 

 the muschelkalk and quadersandstein given by M.Humboldt in 

 his " Essai sur les Gisement des Roches," and that inserted by 

 Dr. Bout: in his Memoir on Germany published in the Journal de 

 Physique. 



We proceed to extract M. Brongniart's notice on Magnesite: 

 " The distribution of the rocks and minerals entering into the 

 composition of the crust of the globe, may be regarded in differ- 

 ent points of view, and the different kinds of relations subsisting 

 between these: bodies successively examined. 



" Sometimes we take a formation composed of different kinds 

 of rocks, whose epoch of formation is well determined in one 

 place, and we follow it in other parts of the globe, to see if it 

 preserves the same position, and to study the mineralogical mo- 

 difications it experiences : this point of view is principally geo- 

 logical and secondari/i/ mineralogical. Sometimes we study a 



