NOTES ON THE ORIGN OF CHERT (FLINT) IN THE 

 LOCAL NIAGARA ROCK, 



BY COLONEL GRANT. 



Read before the Hamilton Association, gth May, 1889. 



I confess I am unable to accept a belief entertained by some 

 members of our Association as well as others also, viz. : that our 

 local " chert " on the brow of the escarpment here was derived from 

 the great number of sponges found in this " band." 



Sponges of the Hexactinellid type doubtlessly possessed the power 

 of secreting the silex held in solution in the Primeval Sea to build 

 up what we may call the " skeleton," but it seems quite impossible 

 that a soft, jelly-like organic substance can, of itself, produce the hard, 

 flinty matter in our " Macadamizing band" (12 feet in thickness at 

 the head of the Jolley Cut, but eight feet of the upper part was 

 ground down and removed in the " Great Ice Age") 



AH decaying animal matter appears to me to have possessed 

 the same property of attracting to itself, during the deposition of 

 " the chert band," silex in solution. There is scarcely a fossil found 

 in the lower Niagara limestones which does not present a stunted 

 representative of a like individual enveloped in cherty matter. 

 " Stricklandinia " (Billings) and " Pentamerus " may be named as 

 exceptions, flourishing, probably, at a certain depth of water on or 

 contiguous to " Coral Reefs." 



I wish to call particular attention to an Echinus of the English 

 chalk (in one of your cases) presented to the Museum by your 

 Curator, Mr. Gaviller, for I think even a hurried examination of this 

 interesting specimen may impress on the memory facts which no 

 words can so clearly convey. 



In this " Sea Urchin " we find the entire interior filled with hard 

 flint (chert is merely an impure member of the same family) and 

 since the outer crust is preserved (although the spines are absent, as 

 they usually are now in dead ones) is it not evident that, the silex 

 filling the interior could only have entered by the minute apertures in a 

 soluble state ? I may be permitted to call attention to remarks made 



