78 .. 



... 47 



80 .. 



... 40 



13 . 



... 7 



53 .. 



.... 27 



54 .. 



... U 



7 .. 



... 5 



18 .. 



... 10 



15 .. 



1 



1 ... 



... 1 



5 





11 





364 ... 



... 160 



ANNIVERSARY ADDRESS OF THE PRESIDENT. IxXVU 



Genera. Species. Newly described. 



MoUusca : — 



1 . Cephalopoda 9 



2. Gasteropoda .' 18 ... 



3. Pteropoda 4 ... 



4. Pelecypoda 23 ... 



5. Brachiopoda 18 ... 



6. Bryozoa 5 7 



Echinodermata 15 



Polypi 10 ... 



Amorphozoa 1 



Plantae : — 



P. cellulares 5 ... 



P. vasculares 7 ... 



Total...... 130 ... 



— thus affording an immense addition to our knowledge of the palaeon- 

 tology of this formation. This is followed by a geological descrip- 

 tion of the different beds which constitute the formation, and a tabu- 

 lar view of the distribution and development of the Rhenish or Dcto- 

 nian system, and its principal members throughout the world. 



M. Barrande has published, in the * Transactions of the Bohemian 

 Society of Science,' an interesting account of the parallelism between 

 the Silurian deposits of Bohemia and Scandinavia, in which he points 

 out, first, with regard to stratigraphical conditions, the thinness of 

 the Silurian beds in Scandinavia, as compared with their vast extent 

 and development in Bohemia. According to M. Angelin and Six 

 B. Murchison, the beds of Scandinavia are not above 1 000 feet m 

 thickness, whereas those of Bohemia are probably fifteen times as 

 thick. It also appears that the sedimentary deposits of the two* 

 countries were formed under very different local influences, both with 

 regard to the nature of the elementary substances constituting the 

 rocks themselves, as well as with respect to the vertical arrangement 

 of these substances. Moreover, the palaeozoic beds of Scandinavia 

 have almost universally preserved their original horizontality, while 

 the analogous deposits of Bohemia have been much elevated and 

 disturbed even before the commencement of the carboniferous period. 



With regard to the palseontological relations between the two 

 countries, Scandinavia has not yet afforded nearly so many species as 

 the smaller basin of Bohemia. The different classes of animals also 

 offer remarkable contrasts between the two countries, one species 

 being more abundant in one country, and another preponderating in 

 the other. The great development of Crustacea is a remarkable fea- 

 ture of the Silurian fauna of both countries, and particularly of Scan- 

 dinavia, where no less than 350 species of Trilobites have been 

 registered by M. Angelin, while those of Bohemia only amount to 

 275. In general, however, there is a great resemblance in the fades 

 of the fauna of the two countries, with the sole exception of the fish, 

 one species of which has been found in Bohemia, but none in Scan- 

 dinavia. In neither country have any remains of land or freshwater 

 MoUusca been discovered, or even traces of land vegetation. 



