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tricht ; it is prominent in the well-known quarries of Cunroot, on 

 the east of Fauquemont, and caps the heights on the north-west of 

 Aix-la-Chapelle, from Schneeberg to the west of Laurensberg ; a 

 small outlying portion remaining also on the top of the Louisberg, 

 near Aix. A stratum like this is mentioned by Mr. Forschammer as 

 occurring in a similar place below the chalk of Denmark, on the 

 shores of the Baltic ; and seems also to exist in the Cotentin. 



4. Green-sand formation. — The marly chalk is succeeded by the 

 equivalent of our upper green-sand, or tire-stone (the Planer-kalk of 

 Germany), in some places identical with that of Surrey, Kent, and 

 Wilts; and like that stone is employed exclusively in constructing the 

 interior of furnaces and buildings under water ; extensive quarries for 

 these purposes being worked at Konigsberg opposite to Vaels, on the 

 confines of the Prussian and Dutch territories. In this country how- 

 ever, there is not, beneath the fire-stone, (or at least does not distinct- 

 ly appear,) a stratum of clay, like our gault; but the chalk, becom- 

 ing gradually charged with green particles, passes, in general with- 

 out an intermediate valley, into green and ferruginous sands, obvious- 

 ly analogous to the lower green (or Shanklin) sands of England. 



5. These sands are well exhibited in the hills on the south-west of 

 Aix-la-Chapelle, and, extending beyond the chalk, occupy a large 

 portion of the surface above the coal and mountain-limestone 

 country. Distinct sections of the stratum are seen on the sides 

 of Louisberg close to Aix, and along the road from that city to 

 Liege, — the scenery of which resembles that of theWoburn sand-hills; 

 and on the descent towards the Calamine Works, near Moresnet, 

 beds are found in the sand, analogous to the fuller's earth of Woburn 

 and of Nutfield in Surrey. The fossils which abound in this forma- 

 tion include (along with many species common to them and the su- 

 perior beds, and hitherto not found in England) some species almost 

 characteristic of our lower green-sand ; among which may be men- 

 tioned the Trigonia aliformis, and Rostellaria Parkinsoni. The 

 sands, at the Louisberg, include a thin bed of lignite; and near the 

 bottom of the formation at Gemenich, and thence along the foot, of 

 the hills to Eynatten, a l'emarkable stratum of grit from 6 to 10 

 feet in thickness, of great firmness and uniformity, occurs, — resem- 

 bling in its characters the grey-wether stone of England, &c. and 

 possibly the equivalent of some of those beds of conglomerate which 

 occur in our green-sand, (the Bargate stone of Surrey, &c.) though 

 differing from them in external character. The ferruginous sands of 

 Grafenberg and other hills on the east of Dusseldorf, belong also to 

 this formation, containing the same fossils as at Aix-la-Chapelle, and 

 occupying a similar unconformable position above beds of lime- 

 stone ; a striking section of which is visible on the banks of the 

 Dussel, at Neanders-Hohle. The sands extending from thence to 

 the north and eastward into Germany, are there well known under 

 the denomination of Quader-sandstein. 



6. In some places, the more ancient strata come in beneath the 

 green-sands without any intervention ; in others, there are indica- 

 tions of intermediate beds of clay, but too indistinct to admit of as- 

 certaining their relations. 



