FORMATION OF NORTHERN GERMANY. 153 
in the upper chalk the first true Turritelle, which, we at least, 
have not seen from any older deposit. Several large species of 
Pleurotomaria still occur ; Trochus and Turbo have likewise nu- 
merous representatives. Cerithium binodosum is for the greater 
part more allied to the more recent species than to the older. 
Delphinula is probably wholly absent in the older deposits. 
With respect to the Cephalopods—we have Nautilus, with few, 
but very widely distributed, species. The Belemnites of the lower 
greensand are neither furcated nor have a fissure inferiorly ; the 
few belonging to the upper chalk have a fissure in front at the 
base, and with these this peculiar race, so prolific in species, dies 
out :—and with them the more beautiful Ammonidee disappear. 
Of these the Falcifere and Amalthee no longer occur in the chalk 
formation ; and only the forms which resemble A. Lamberti, in 
the Hils-clay. The Planulate and Dorsate are still tolerably fre- 
quent in the older chalk deposits, and appear to become extinct 
in the gray chalk. The Macrocephale, Ornate, Dentate and Ar- 
mate continue most frequent. The Ammonites of the chalk are, 
as their most talented friend (Von Buch) says, in general sickly *; 
many appear too weak to be able to combine the earlier convo- 
lutions: these are therefore left free, as in (Hamites); and are at 
last straight (Baculites). Similar causes have also produced the 
Scaphites and the Turrilites. Ammonites bidorsatus, Baculites 
anceps, Hamites intermedius, Turrilites undulatus, Scaphites in- 
flatus and binodosus, appear to be the last of their respective 
races :—their latter days they passed amidst a legion of minute, 
chiefly microscopic, delicate, allied forms, among the Rhizopods 
(Foraminifera ?). These last-mentioned forms we meet with for 
the first time in the Hils, the lowest clay of the lower greensand, 
in large quantity; and they are so frequent in the white chalk 
that this stratum consists perhaps altogether of a deposit of their 
shells; the majority of their tertiary genera likewise occur in the 
chalk formation; Agathistegie, however, appear to be wholly 
absent. 
Annelide are numerous, but offer little remarkable. 
Among the Crustacea,—Cytherine are not rare in the Hils-clay 
and the upper chalk; they are all very similar to the tertiary 
species. Pollicipes first occurs in the Hils-clay ; Balanus in the 
Hils-conglomerate (lower greensand): the upper chalk deposit 
contains several species of the former genus, and at the same time 
* “Wie ihr gestreichsten Freund sagt, ‘ meist krank.’ ” (Orig.) 
