260 



PROCEELIIS'GS OF THE GEOLOaiCAL SOCIETY. 



of the New York area, and by the very warrantable supposition 

 that the creative force has been exercised in a different manner in 

 the two districts. We observe that the calcareous or deep-sea sedi- 

 ments are much more fossihferous than the arenaceous or shallow 

 bottoms, — although not in the same proportion in our two districts, 



Table YI. — Exhibiting numerically the Sedimentary Habitats of the 

 Silurian Fauna and Flora of Wales and the adjacent English 

 Counties. 



Classes, 

 Families, 



and 

 Orders. 



Plantae 



Annehda .... 

 Amorphozoa. 

 Zoophyta .... 

 Crinoidea . . . . 

 Crustacea . . . . 

 Bryozoa . . . . 

 BracMopoda. 

 Monomyaria 



Dimyaria 



Gasteropoda. 

 Heteropoda . 

 Pteropoda. . . . 

 Cephalopoda 

 Pisces 



Total 



12 



25j 



3 



81 



69' 



154' 

 41! 



1671 

 22, 

 64 

 57| 

 12 

 11 

 50 

 11 



Non-calcareous 

 Sediments. 



17 



779 42 61 142 



OQ 



OQ 



4 



4 



21 



1 



38 



11 



17 



14 



7 



3 



6 



2 





1 

 4 

 1 



17 

 5 



48 

 8 



80 

 4 



33 



18 

 8 

 5 



17 

 1 



1 

 4 



"2 



12 

 41 

 11 

 32 



4 



13! 2 

 10 



5 



4 

 20 



1 



o 



14 

 19 

 1 

 34 

 23 



154 

 30 



207 

 20 

 69 

 57 

 24 

 13 

 47 

 12 



Calcareous Sediments. 



^ 



o 



i . 



§§ 

 O CO 



5 © 

 §.§ 



25 

 14 



47 

 11 

 80 



9 

 24 

 23 



8 



3 

 15 



3 



I 



m 

 O 



13 



ie 



4 



32 

 3 



65 

 9 



24 



15 

 6 

 8 



22 

 3 



250 160 69 724' 267 220 173 306 37 1003 1727 



•5b 



3 

 2 

 19 54 



2, 39 

 34 49 



7 23 

 70: 79 



31 6 



5 3 

 10 23 



3 



2 



11 



2 



4 



19 



a, 



o 



30 

 2 



121 

 59 



169 

 45 



309 

 27 

 57 

 75 

 19 

 17 

 67 

 6 





O 



14 



49 



3 



155 

 82 



323 

 75 



516 

 47 



126 



132 

 43 

 30 



114 

 18 



being as eight to one in New York, and two to one in Wales. The 

 animal life of this period is most abundant in moderate depths, as 

 indicated by limestone containing a good deal of alumina. Annelida. 

 Crustacea, Brachiojpoda, Lamellibranchiata, Gasteropoda, Hetero- 

 jooda, and Cephalopoda — a vast series of existences — occupy almost 

 every form of sediment ; the same species occur, as we shall see, 

 in very many. The Plantce, both in New York and Wales, require 

 further study. The majority of the North American forms, so de- 

 nominated at present, will probably be resolved into the casts of 

 the intestinal canals of great Annelida (Salter), — their contents, 

 in fact, at the time of death more or less changed in mineral cha- 

 racter. If so, we shall be justified, with Mr. Salter, in considering 



