PAPERS OX BIOLOGY AND AGRICULTURE 221 



50 very narrow rings while one of 10 inches showed 75 

 rings divided into zones which varied considerably in the 

 thickness of their rings. On account, perhaps, of the 

 dense shade and the carpet of needles the undergrowth 

 in the center of the forest was scanty but contained much 

 minium, some patches of marchantia, one species of aster 

 and some fungi, especially several specimens of Helvella. 

 The southern portion of this forest and the western grove 

 are less dense and the trees are smaller. 



The swamp zone is narrow along the west side and on 

 the east side below the northern basin which contains the 

 lake, but the western depression has wide extensions both 

 to north and south, which are filled with grass hummocks 

 with occasional specimens of dwarf birch. The shrub 

 zone is narrow and scanty toward the north, the chief 

 species being Cornus paniculata and saplings of balsam 

 poplar. From the center south and west it consists of 

 an almost pure stand of swamp sumach which, taken with 

 the specimens on the Saver bog, constitute much the 

 largest display of this plant to be found in the State. The 

 topography of the bottom of the original depression is 

 similar apparently to those of the other depressions, — 

 shallow in the swamp zones but much deeper under the 

 tamaracks. Where the swamp zone is narrow, the bottom 

 drops away rapidly, but in the broad bay-like extensions 

 the slope is very gentle. 



The last bog of those so far studied is located in the 

 N. W. corner of Section 35, T. 46 X., R, 10, E. about a mile 

 west of the village of Millburn. In many respects it re- 

 sembles the one located northeast of the Saver bog, but 

 it has some distinctive features of its own. There are no 

 tamaracks visible and no sign of their former presence 

 although, as there was no ditching going on, there was 

 nothing to show whether or not a former forest had been 

 cut in the past. 



The depression is a broad oval extending northeast and 

 southwest and measures about 500 yards by 300, bordered 

 by the usual swamp zone which is narrow on the north 

 and east, but with broad extensions to the south and 

 southwest. Within this swamp zone the substratum is 

 covered bv a thick mat of sphagnum with much cranberry 



