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GEOLOGICAL MEMOIRS, 



ing order) of the component groups of the Aix-la-Chapelle series is 

 given at p. 5. 



Divisions. Feet (German). 



{1. Aix-la-Chapelle Sand with intercalated 

 clay-beds (Aix-la-Chapelle Chalk-loam 



[Aachener Kreideletten]) 250 to 300 



II Middle -[ ^' ^ ower Greensand of Aix-la-Chapelle 15 — 50 



1 \ 3. Gyrolite-greensand 10 — 50 



f 4. Upper Greensand and chloritic Chalk 5 — 10 



III. Upper ...... | ■ Chalk . marl j a Without Firestone 5 - 50 



[ \b. With Firestone 5 — 50 



{q J Lusberg Breccia 1^ — 2 



\ Vetschau and Kunraed Chalk-marl 15 — 50 



7. Vetschau and Kunraed Coral-chalk 6 — 10 



8. Hornstone 



9. Valkenberg and Maestricht Chalk-tuff 5 — 250 



The last (No. 9) does not occur in the district under consideration. 



The fauna and flora of the "Lower Division" of the above series 

 are of considerable interest. It is subdivided by the author into three 

 groups. 



The lowest exposed beds of the " Aix-la-Chapelle Sand" contain 

 but a small proportion of vegetable remains. 



The middle group is remarkable for the great abundance and 

 variety of its flora. It contains remains of delicate stems, leaves, 

 flowers, and fruits, and the resin of Conifers. The epidermis of 

 whole leaves sometimes occurs in a slightly carbonized state, and re- 

 cognizable by its microscopic structure. Xylophagous Molluscs are 

 found in the petrified and carbonized wood, and Infusorial remains 

 occur in the clay. 



In the upper group, the sandstones contain a great quantity of 

 vegetable detritus, amongst which occur some branches, with or 

 without fruits (Cycadopsis). Very rarely a few marine organic re- 

 mains accompany the above (Cardium Becksi, Mull.). In the Sand- 

 beds a few marine remains have been found, viz. Turrit ella and Tri- 

 gonia alceformis. Lastly, a small local patch of peculiar sandstone 

 affords Ostrea vesicularis (very rare), a quantity of other Ostrece, a 

 Gasteropod resembling Cerithium, and which, although it reminds 

 one of Turritella costulata, Goldf., from the Oolite, is nevertheless 

 peculiar to this sandstone ; also a fragment of a large Tornatella, a 

 new Patella, and another. 



A comparative view of the palaeontology of the different members 

 of the Chalk-formations of Aix-la-Chapelle, Bohemia, and England, is 

 given in a tabular form, and is succeeded by a consideration of the 

 Cretaceous Flora ; especially of Saxony, Silesia, and Aix-la-Chapelle. 

 By its richness in Algce and Ferns, &c, says the author, and by 

 its poverty in Cycadece does the Aix-la-Chapelle Cretaceous flora 

 differ from most of the others. The Conifer ce and partially the 

 Dicotyledonous leaves, however, indicate an evident relationship. 

 The Cunninghamites (Saxony, Bohemia), Geinitzia (Bohemia), 

 Araucarites (Bohemia), and the Lycopodites (Saxony), which pro- 

 bably belong to the Conifers, are forms decidedly allied to the Cyca- 



