244 PROCEEDINGS OF THE ACADEMY OF [1888. 



meters in length ; the former is the more common and in a very- 

 perfect state of preservation. 

 Diplodus sp. ? 



From the superimposing shales of coal No. 3 at the Giant mine. 

 The specific characters of the teeth collected have not been satisfac- 

 torily made out. They are evidently not far removed from D. 

 amplicattis M. and Worthen, but the denticles are larger, more 

 slender and much longer than in that species. 



Synoptical Table of Genera and Species. 



Coelenterata Polypi genera 1 species 1 



Echinodermata Crinoidea 1 1 



Vermes j Brachiopoda 9 14 



( Bryozoa 1 1 



JLamellibranchiata 7 9 



Gasteropoda 10 20 



Cephalopoda 2 5 



Crustacea. 2 2 



Vertebrata 2 2 



Summing up the predominant faunal features as presented in the 

 accompanying synoptical table, it appears (1) that in those groups 

 having an optimum habitat marine there was not only a fewness of 

 species but also an extreme paucity of individuals ; (2) that braeh- 

 iopods though well represented in both genera and species were in 

 fact not as proportionately abundant as might be expected when it 

 is remembered that this type of life had now nearly reached its 

 greatest expansion and culmination, and (3) that the fauna was 

 predominately molluscan — nearly two-thirds of the entire number 

 of species. 



The Coelenterata, Bryozoa and Echinodermata form indeed a very 

 inconspicuous proportion of this local fauna, only three or four spe- 

 cifically distinguishable traces of each group being obtained. 

 Though the Brachiopoda are represented by fourteen species, in- 

 cluded in nine genera, they were with three exceptions of compara- 

 tively rare occurrence — Productus murieatus, Chonetes mesoloha and 

 D'iscina nitida only being abundant. The brachiopods are also all 

 depauperate, attesting conditions at the time that they lived ex- 

 tremely unfavorable to their full development and to the attainment 

 of a normal size that under more cong-enial circumstances would 

 have been rendered possible. Molluscan life, while the black shales 

 forming the roof of coal No. 3 were being laid down, flourished 

 luxuriantly, especially the gasteropods which in number of species 



