76 On the Silurian Focks of Bohemia, and 



tamenes Knightii of the middle limestone of the Ludlow rock, 

 and in Bohemia, as in England, it is associated Avith the 

 well-known Terehratula TFilsoni. In reference to the trilo- 

 bites which occur in the upper Silurian of Bohemia, I hope I 

 may be excused for saying, that T was peculiarly gratified 

 to observe, that the lower stage of the limestones of this 

 age contains, as in England, the Bumastus (mihi) ; and that 

 of the two species collected by M. Barande, one is scarcely 

 distinguishable from my B. Barriensis. Now, while I state 

 with some confidence, that no such species has been found in 

 the lower Silurian rocks, I equally maintain (mere geologist 

 as I may be), that, despite of the criticism of the learned 

 naturalist Barmeister, the genus Bmnasdis, as defined by 

 me, is well established, and never can be united, as he sug- 

 gests, with the true lower Silurian genus Illconus, from which 

 it is at once distinguished, by its completely round and pei*- 

 fectly untrilobed (without trilobation) pygidium, whilst it is 

 as absolutely separated fi'om Nileus, by the number of seg- 

 ments in its body. 



If time permitted, I could now run on in enumerating a 

 remarkable number of additions to the natural history of 

 geology, which will be made known and illustrated by the 

 work of M. Barande ; but intending to give you a mere out- 

 line of what may be expected from him, I may inform you, 

 that amid many analogies and identities, to some of which I 

 have already alluded, the Brachiopoda alone offer about 30 

 species which are absolutely identical with British and Silu- 

 rian types. 



I will now conclude this letter, by informing you that Count 

 Keyserling, De Verneuil, and myself, have examined the ti'act 

 around Olmutz, subsequent to our visit to Prague. When 

 Professor Glochar of Breslau, sent to your Journal a brief 

 communication on the natnre of the limestone of Rittberg, 

 and the environs of Olmutz, surmising that it was of Silurian 

 age, your valued coadjutor, M. Brown suggested, in a note, 

 tliat it was probably, however, of Devonian age, as the fossils 

 were like those of the Eifel. Since then, some additional 



* See Jahrbuch, 1842, p. 42. 



