1910] The Ottawa Naturalist. 147 



NOTES. 



Clay Nodules. In the account of the September excursion 

 to Green's Creek, which appeared in the October issue, a mention 

 was made of the interesting clay nodules, which occur there in 

 such numbers. Since, the Editor has received from Dr. Percy E. 

 Raymond, of the Geological Survey, some notes on these nodules, 

 which will undoubtedly be of interest to our readers. 



' ' Toward the end of the ' Great Ice Age ' there was a lowering 

 of the northeastern portion of the North American Continent 

 with respect to the sea level, and, as a result, the great river 

 valleys became, for a time, arms of the sea. One of these arms 

 extended up the St. Lawrence as far as the upper end of Lake 

 Ontario, with a side bay which occupied the Ottawa Valley for 

 at least 200 miles west of Montreal. Another covered the region 

 occupied by Lake Champlain, whence the name 'Champlain 

 epoch." often applied to this time. At that time, as now, the 

 rivers, descending from the low highlands to the north and west, 

 brought down sand and fine mud wdiich was deposited over the 

 sea bottom. With the mud came quantities of leaves from the 

 northern forests, and occasionally, insects, feathers of birds, and 

 bones or bodies of animals. In the sea itself lived such a fauna 

 as is found off our northeastern coasts; whales, seals, various 

 fish, barnacles and bivalves. As the anmials died, their bodies 

 or shells were buried in the constantly accumulating mud, and, 

 being protected from rapid decay by the exclusion of the air, 

 the harder portions have been preserved as fossils such as are 

 found in the nodules at Green's Creek and Besserer's Grove. 



"The exact method of formation of these nodules, or any 

 nodules, is hardly known, but it seems probable that the acids 

 which are the product of the decay of the organic matter had 

 something to do with the formation of the cement which has 

 hardened the clay for from one-half an inch to one inch in all 

 directions from the fossil which forms the nucleus. It is, indeed, 

 remarkable how closely the outline of one of the nodules follows 

 the specimen within it. 



"These nodules have furnished quite a fauna and flora, 

 thanks to the persistent collecting of Dr. Ami and the members 

 of the Field- Naturalists' Club. Nearly all the forms belong to 

 species living at the present time, though a few, notably the 

 insects, are now extinct. The fauna and flora are interesting as 

 showing an instance in which organisms representing the life 

 of both sea and land are preserved in the same bed, and as show- 

 ing the great physical and climatic changes which may take 

 place in a (geologically) short time. Sir William Dawson said 

 of this flora that it 'represented the greatest refrigeration of 



