196 The American Geologist. September, 1903. 
bog again. The forest vegetation on it consists of spruce, larch, wil- 
lows, cedars (Thuja occidentalis) etc., and small shrubs. An old 
cedar in one part of the bog was cut down and its growth rings ex- 
amined ; assuming that each ring represented a year of growth of the 
tree, it was 400 years old: in other words the seed from which it 
sprang germinated about the time Columbus discovered America. The 
roots of this tree had spread themselves chiefly at two levels in the 
moss of the bog, one at three inches, the other at six inches below the 
"surface ; below this were no roots, but the smooth, rounded base of the 
tree. Since this tree germinated only six inches of mould and moss 
had accumulated over the surface of the bog; yet this bog is eight 
feet deep, and plainly seen to be of continuous forest and bog growth 
since the marsh, that followed the breaking down of the beaver pond, 
gave place to peat. The calculation is a very simple one which enables 
us to deduce 6000 or 8000 years as the period required for the growth 
of this bog. 
Yet the growth of this bog, of marl deposit in the lakes, and of 
other surface accumulations occurred in what is called the Recent per- 
iod. The close of the Terrace period saw the beginning of the growth 
of this bog, so that it may be said that the Terrace period and the 
Champlain period separated its history from that of the Glaciers. It 
is to these what the Neolitic is to the Palaeolithic age in Europe, and 
hence a comparatively short episode; at least it has this relation if we 
include in the latter the Eolithic. 
It seems highly probable that when we obtain a closer insight into 
the value of these later geological phenomena, and a fuller knowledge 
of the surface deposits, we will be inclined to add to professor Upham's 
average estimate of the Post glacial ages rather than take from it. 
G. F. MATTHEW. 
PERSONAL AND SCIENTIFIC NEWS, 
Dr. W. D. Matthew returned Aug. 1st from several 
weeks in the field in Wyoming and went on to New Bruns- 
wick for additional work. 
The National Association of State Mining Schools 
will meet in Deadwood, South Dakota, next month (Septem- 
ber) during the session of the American Alining Congress. 
Dr. E. O. Hovey sailed August 6th by the Moltke of the 
Hamburg American line. He will represent the American 
Museum of Natural History at the International Congress in 
Vienna. 
Professor A. N. Winchell, of the Montana School 
of Mines, has been placed in charge of the mineral exhibit to 
be made at St. Louis next year by the Montana World's Fair 
Commission. 
