NOTES ON THE NATURAL HISTORY AND PHYSIOGRAPHY OF N. B. 127 



their siliceous shells gradually sink and become compacted, thus form- 

 ing the valuable siliceous deposits (infusorial earth) often dredged 

 from lakes fur economic use under the name of "Fossil Flour." It is 

 thus no doubt the great beds of diatomaceous earth were formed in 

 past geological periods. 



Another lake of this kind appears to be the Fifth Green River 

 Lake, which according to J. W. Bailey (" The Saint John River," 

 page 53) is " very shallow with a soft bottom of white mud, which the 

 men call ' paint,' from its quality of sticking to the canoe-poles, like 

 white lead." Of course there are plenty of others, and the question 

 at once arises, whether the brown mud which gives the name " Mud 

 Lake " to dozens of small shallow lakes in Maine and New Brunswick 

 may not be of essentially the same nature, the different color resulting 

 from admixture of peaty matters or other impurities. In any case it 

 is a problem to determine what favors the growth of these organisms 

 in some lakes and not others, and why they are so much purer in 

 some than in others. Here is a good place for the student of the 

 freshwater Algae of New Brunswick to begin his labors upon the most 

 attractive group of Plants yet unstudied in our Flora. 



To the unaided vision, nothing could be more unattractive than 

 the muddy bottoms of these lakes ; but with the microscope to aid, 

 they become replete with a beauty of form hardly to be matched else- 

 where in Nature. 



18. — Preliminary Outline of a Plan for a study of the Precise 



Factors determining the Features of New Brunswick 



Vegetation. 



[Read December 6th, 1898.] 

 The most marked tendency of botanical investigation at the pres- 

 ent day is towards the elucidation of the dynamical factors determining- 

 structure and distribution in Plants. In the study of local Floras, it 

 is taking the form of an attempt to find out the exact factors which 

 place each plant where it is, and make it the size, form, color and 

 texture it is, a discipline known as Ecological Plant-geography. 

 Though a new study, many valuable contributions to it have already 

 appeared in Europe and this country, and a great extension of the 



