304 Figures and Descriptions of Canadian Organic Remains. 



occupied by these formations scarcely a vestige of a Cystidean is 

 to be found ; but in other places, such as the neighbourhoods of 

 the cities of Montreal and Ottawa, they are exceedingly plentiful. 

 Everywhere however good specimens are rare. 



" M. Barrande, in comparing the European rocks of this age, 

 observes that in Bohemia the Cystidean zone occurs about the 

 centre of his stage of Quartzites D, which would be also the 

 equivalent of Angelin's group C. In England the corresponding 

 level would be about the Bala limestone, where the principal masses 

 of Cystidese are found. The abundance of their remains in the 

 Chazy and Trenton of Canada confirms the views of M. Barrande, 

 and at the same time tends to shew that these two American 

 formations should be paralleled with the Bala rather than with the 

 Llandeilo. This question however cannot be decided without 

 more perfect lists of fossils than can be at present procured. 



"The number of species of Cystideae that occur in this zone are 

 as follows, so far as I can ascertain, in these countries respectively : 



Scandinavia and Russia 20 



Great Britain 13 



Bohemia, about 8 



Canada 21 



N ew York 1 



63 



" In consequence of the imperfection of the specimens and some 

 confusion in the descriptions of different authors, the above num- 

 bers may not be exactly correct ; but from what I have seen it 

 appears to me that there are more than sixty species, described and 

 underscribed, belonging' to this period. 



" In the Upper Silurian there are in Great Britain nine species, 

 and in Canada and New York about the same number, but none 

 in either Bohemia or Scandinavia have yet been made public. 



" According to the present state of our knowledge, then, in the 

 lower half of the Lower Silurian there are four species, in the 

 upper half sixty-three, and in the Upper Silurian eighteen. 



" Very little dependence however can be placed upon numerical 

 comparisons, such as the above, in dealing with questions relating 

 to the Cystideae or Crinoidese, for the reason that new discoveries 

 are every year being made which very materially change the aspect 

 of these computations. For instance, six years ago only eleven 

 Crinoids, one Cystidean, and one Star-fish, were known in the 

 Lower Silurian of New York and Canada, but in the collection of 



