7 2 JOURNAL AND PROCEEDINGS 



On the left bank of the Thames River, near Komoka, I 

 noticed a spring in a wood close to the stream holding silica in 

 solution. There were some fresh-looking chips of hardwood lying 

 at the bottom, and, on fishing them out, I found they were silicified. 

 This spring arises from " Corniferous drift." I cannot say whether 

 it has a deeper origin. "The drift" itself contains a good many 

 white sandstone boulders. So, acidulated waters, percolating through 

 it may carry off a certain portion of the silex overlying. 



Origin of Chert or Flint. — In my younger days the view enter- 

 tained by geologists, respecting the origin of the flint in the English 

 Chalk, was, that it was derived from mineralized heated springs at 

 the bottom of the " Primeval Seas " — -there were few found hardy 

 enough to dispute what was almost universally supposed. Now, 

 as I never had an opportunity of examining " the English chert 

 of the chalk in situ," I can form no opinion with regard to it, but I 

 may say I have failed to obtain any evidence whatever of " Thermal 

 Springs " arising from the sea bottom, when our local chert band was 

 deposited. And I would venture to remark it was more probable 

 that the silica was originally derived from acidulated water carrying 

 down the matter from " The Laiirentian Highlands" quartzites 

 and the granitic rocks which formed the northern boundary of this 

 Silurian (Mediterranean) Sea. That this continent possessed such, 

 is admitted by leading geologists in Canada and the States. It is 

 well known that the succeeding rocks of the " Devonian " and 

 " Carboniferous Ages " also contain a large amount of cherty lime- 

 stone. A striking characteristic of these and some other limestones 

 of the "coal measures," remarks Dr. Newberry, is the quantity of silex 

 they hold locally. The Zoar limestone becomes so cherty as to be 

 called flint or burr-stone. In other portions of the coal field the 

 higher beds exhibit the same phenomena. 



The origin of the silex in these flinty limestones, he adds, has 

 never been satisfactorily explained. It has sometimes been attributed 

 to hot springs, of which the water contained much silica, but the 

 general distribution of the flint and the number of fossils contained 

 in it, seem to me insurmountable objections to this view. It is more 

 probable that the silica was derived from microscopic organisms, 

 such as the "diatoms." It seems to me quite possible the individual 

 forms have disappeared by solution, and that the moss has been 

 converted into compact silica, such as we find in "chert beds," 



