NATIVE VEGETATION. 187 



Doubtless they occur also at other points that escaped my knowl- 

 edge. AYhen it is considered that the size of the district required 

 the inspection of from 3,000 to 4,000 square miles each season, some 

 omissions in matters not specifically geological will doubtless be par- 

 doned by a generous public. 



The elements of success in cranberry culture, so far as they are rel- 

 evant here, seem to be the following, as I glean from several author- 

 ities: 



I. A Suitable Bottom. A good bed of peat is the best, that being 

 the principal food of the plant. At the east, cedar swamp bottoms 

 are preferred by many. Our tamarac swamps will doubtless be 

 equally satisfactory; indeed, native cranberries are sometimes found 

 growing on them. 



II. Facilities for drainage, and complete control of it, so that the 

 marsh may be drained or flooded, as may be demanded. 



III. A Sufficient Supply of Silica. This is sometimes already 

 present, but is usually to be supplied by covering the surface with 

 sand. "Silica plants" differ from "peat plants" in appearance and 

 mode of growth, and in yielding at least three times the amount of 

 fruit produced by the latter. The successful culture of the cranberry 

 is also limited to certain latitudes. If too far north, the early frosts 

 prevent their maturing and render them a precarious crop. If too far 

 south, the heat interferes with their proper development. Actual ex- 

 perience is the best guide in respect to this, as well as the other con- 

 ditions, and hence the value of observations on the experiments that 

 Mature has herself made. 



