Ch. XV.] STRATA IN" NORTH GERMANY. 189 



dant ; a fossil unknown as yet in the English tertiary strata, but when 

 young much resembling Leda amygdaloides of the London clay proper 

 (see fig. 227, p. 218). Among other characteristic shells are Pecten 

 Hoeninghausii, and a species of Cassidaria, and several of the genus 

 Pleurotoma. Not a few of these testacea agree with English Eocene 

 species, such as Actceon simulatus, Sow., Cancellaria evulsa, Brander, 

 Corbula pisum (fig. 170, p. 193), and Nautilus ziczac. They are accom- 

 panied by many teeth of sharks, as Lamna contortidens, Ag, Oxyrhina 

 zipkodon, Ag., Carcharodon heterodon (see fig. 211), Ag., and other fish, 

 some of them common to the Middle Eocene strata. The same deposit, 

 B. 1, is very imperfectly seen at Kleyn Spawen, where the lower divisions 

 B. 2 and B. 3 are much better developed. B. 2 consists of several alter- 

 nations of sands and marls, in which a greater or less intermixture of 

 fluviatile and marine shells occurs, implying the occasional entrance of a 

 river near the spot, and possibly oscillations in the level of the bottom of 

 the sea. Among the shells are found Cyrena sernistriata (fig. 171, p. 

 193), Cerithium plicatum, Lam. (fig. 172, p. 193), Rissoa Chastelii, 

 Bosq. (fig. 174), and Corbula pisum (fig. 170), four shells all common to 

 the Hempstead beds in the Isle of Wight, to be mentioned in the sequel. 

 "With the above, Lucina Thierensii, and other marine forms of the genera 

 Venus, Limopsis, Trochus, &c, are met with. 



In B. 3, or the Lower Limburg, more than 100 marine shells have been 

 collected, among which the Ostrea ventilabrum is very conspicuous. Spe- 

 cies common to the underlying Brussels sands, or the Middle Eocene, are 

 numerous, constituting a third of the whole ; but most of these are feebly 

 represented in comparison with the more peculiar and characteristic shells, 

 such as Ostrea ventilabrum, Mytilus Nystii, Voluta saturalis, &c. 



In none of the Belgian Upper Eocene strata, could I find any nummu- 

 lites ; and M. D Archiac had previously observed that these foraminifera 

 characterize his " Lower Tertiary Series," as contrasted with the Middle, 

 anc would therefore serve as a good test of age between Eocene and Mio- 

 cene, if the line of demarcation be drawn according to his method, or 

 equally so between Upper and Middle Eocene, according to the plan 

 adopted in this work. The same naturalist informs us that one nummu- 

 lite only has ever yet been seen to penetrate upwards into the middle 

 tertiary, viz., Nummulites intermedia, an Eocene species. It has been 

 found in the hill of the Superga near Turin,* in beds usually classed as 

 Miocene, but probably somewhat older than the falunian type. 



Hermsdorf, near Berlin. — Professor Beyrich has described a mass of 

 clay, used for making tiles within seven miles of the gates of Berlin, near 

 the village of Hermsdorf, rising up from beneath the sands with which 

 that country is chiefly overspread. This clay is more than forty feet 

 thick, of a dark bluish-gray color, and, like that of Rupelmonde, contains 

 septaria. Among other shells, the Leda Deshayesiana before mentioned 

 (fig. 167) abounds, together with many species of Pleurotoma, Voluta, &c, 



* Archiac, Monogr. pp. 79, 100. 



