of the Prussian States. 101 



or species of coke, in the lowest bed of the gallery of Friedrich 

 Wilhelm Erbstollen, in consequence of a porphyritic mass 

 which rises from the interior of the earth, and covers it in an 

 irregular manner*. The author mentions two similar exam- 

 ples in the fifth coal bed of Lauragrube, and in the second of 

 the Gnade-Gottesgrube mine. 



The coal deposit of the circle of Saale is situated to the N. 

 and N. W. of Halle, fills cavities, presents saddle-shaped 

 strata, and has many dips and directions. The secondary red 

 sandstone covers the coal measures, porphyries rise through 

 it, and raise the coal beds to the surface. The coal measures 

 of Saarbruck are situated at the bottom of a bay formed by the 

 Hunsdruck and the Vosges. The beds run fi-om S. W. to N.E. 

 and incline to the N.W. They are rather irregular, espe- 

 cially in the N.E. part, and present many contortions. The 

 dip of the Saarbruck beds is in general at about 20°. The 

 coal deposit on the Worm, N. and N. E.' of Aix-la-Chapelle, 

 forms a separate basin in the submedial or transition rocks, 

 and contains thirty-four known beds of coal. The coal basin 

 of Eschweiler resembles the preceding, contains forty-six beds 

 of coal, is 5500 yards long, and 2250 yards wide. The thickest 

 coal bed is from four to six feet in depth. The coal deposits 

 of La Mark occupy three basins, run from S.W. to N.E. 

 Many mines traverse the cretaceous chlorite marl, which co- 

 vers the coal at Unna, &c. These rocks rest on submedial or 

 transition rocks, and are separated from them by a thick mass of 

 coal sandstone, without workable coalf. The coal deposits of 

 Tecklenburg-Lingen are situated near Ibbenblihren ; there 

 are tin-ee beds of coal; the first and second run E. and W., 

 and dip N. at an angle of 12^ or 15°; and the third runs 

 from E.N.E. to S.E., and dips N.W. at 6° or 10°. The first 

 is three feet thick, the second from five feet to five feet seven 

 inches, and the third a foot and a half. Its geological rela- 

 tions are unknown X. 



Lastly; The coal deposit of the Shaumburg, nearMinden, 

 lies parallel to the Teutoburgerwald, in the chain of the 

 Wichengebirge, which extends to the S. and W. of Minden, 



on 



• Tliesc additions to similar facts already known are important, as they 

 tend to coniinii, if that were necessary, the now almost {;encra!ly received 

 opinion of the ianeoiis origin of trap rocks. — Trans. 



f May not this be the ccjuivalcnt of our millstone grit? — Trans. 



i Tile coal deposits, enumerated as far as this in the text, would appear 

 to be referable to the coal measures; that of Tecklenburg-Lingen (which 

 follows), slated to occur in the lias maris, is important, wlun coupN-d with 

 Mr. Murciuson's very interesting ccmnumication (o the (icolo^icil. Society, 



rcspcctim; 



