3U) HULLETIX OF THE NATURAL HISTORY SOCIETY. 
Indications of differences of salinity, and decrease of the 
latter with increase of distance from the sea, are to be found not 
only by observations for density, but also through the effects of 
evaporation upon the slides used for microscopic examination. 
In the case of all those about the Narrows, the saline matter was 
such as to obscure observation, making repeated washings 
necessary, but this effect became less as the point of collection 
was more remote from the mouth of the river, and at the most 
remote points was barely perceptible. From the character of 
the crystallization it would also appear that the more soluble 
magnesian salts, together with sulphate of soda, have a wider 
distribution than common salt or sodium chloride. No chemical 
analyses of the water have yet been made. 
THE “ INFUSORIAL EARTHS ” OR TRIPOLITES OF 
NEW BRUNSWICK. 
These have as yet been observed at comparatively few points, 
but it is altogether probable that further search will reveal their 
presence at many other localities. They are usually found on 
the bottom of shallow ponds or small lakes or beneath beds of 
peat. They present the appearance of chalk-like deposits, some- 
times of chalky whiteness and easily reducible to powder; in 
other instances colored grey by the ]wesence of organic matter, 
or yellowish from the presence of hydrous peroxide of iron. 
Such deposits are of some economic value and have been 
applied to a variety of uses, such as absorbents of nitro- 
glycerine in the manufacture of dynamite, as filling material in 
the making of paper, in the manufacture of soap and water- 
glass, as abrasive material in polishing powders, and for other 
uses. They are also of interest to the geologist, as from the 
character of the contained species it is possilfie to determine 
whether they are of purely lacustrine or marine origin, and 
therefore to indicate former changes of level in relation to the 
sea. It is possible that in some instances the lower layers of the 
