I£>o Observations on Trilobites. 



of the Mohawk in a north-western direction, as far as the eye 

 can reach. At the Little Falls, the same formation was found 

 constituting the western side of the Falls Mountain, but 

 whether superincumbent or subjacent, was not determined, 

 Eaton inclines to the former opinion, and states that this for- 

 mation extends to Lake Ontario. 



Chemical and external character. The higher strata are 

 composed of carbonate of lime nearly pure, of a light gray 

 colour, and crystalline structure, easily separable into rhombic 

 crystals ; they may be readily burned into lime, and are much 

 used for that purpose. At greater depths the substance be- 

 comes more compact, of a darker gray colour, and finally 

 quite black. It is then highly fetid, and unfit for the purpose 

 of burning into lime in the usual manner ; it still, however, 

 effervesces violently with acids. No nodules of horn-stone 

 were perceived in any part of the rock. The lower strata 

 are susceptible of a high polish, and might probably be ad- 

 vantageously worked as quarries of black marble, being fully 

 equal in beauty to the Luculliie of Derbyshire. 



Mineral contents. No mineral contents of any value were 

 observed ; in some few cases, the contained petrifactions were 

 found to consist of sulphuret of iron. 



Organic remains. The animal remains contained in every 

 part of the rock, are extremely abundant, in some cases mak- 

 ing up nearly the whole mass. No remains of vertebral ani- 

 mals have been observed in any of the specimens brought 

 from this locality, or in the rock itself. 



Encrinites and Fungites (of Knorr) are found in great 

 quantities, some of the strata contain no other petrifaction 

 than the former, and they are copiously disseminated through 

 them all. 



Trilobites frequently occur ; the Dudley fossil ( Calymene 

 Blumenbachii of Brongniart) was at once readily distinguish- 

 ed ; another unknown to the observer was found, which it ap- 

 pears has not hitherto been described; this, after attentive 

 ^tamination, was determined to belong to a new genus, and 



