Marcu 7, 1884.] 
ly defined on its equatorial side, diffused upon 
its polar side, and gathered in places into wispy 
notches and curved markings. The color was 
a vandyke brown. Several other belts of dif- 
ferent tints were interposed between this one 
and the pole. Other observers mention the 
existence of loops somewhat resembling the 
markings on Jupiter. The planet is now too 
far past its opposition to be well observed dur- 
ing the present season; but the opposition of 
December next will be yet more favorable for 
observations, and will, we hope, be taken ad- 
vantage of by all possessors of telescopes. 
LETTERS TO THE EDITOR. 
** Correspondents are requested to beas brief as possible. The 
writers name is in all cases required as proof of good fuith. 
Arrow-points at Evanston, II. 
In the sand-ridge at Evanston, just back from the 
beach, and which follows the shore more or less 
SCIENCE. 
213 
flint-chippings for an area of several square yards, 
marking spots where formerly stone implements were 
chipped. The very fresh appearance of the chippings 
upon the surface at this remote day, as if just dropped 
there, is accounted for by the sweeping of the wind 
from the exposed quarter over such localities, win- 
nowing the particles of sand from the heavier flint. 
The chippings scattered in the light soil around the 
operator, while he fashioned the implements, remain 
at the original site; but, as the sand is gradually 
blown away, they appear at a lower level than before, 
and strewed over the hard, smooth surface which the 
wind has left. 
In protected places, on the other hand, where the 
blowing sand accumulates in drifts, chippings, in- 
stead of being exposed, have been covered to a con- 
siderable depth, as excavations in the vicinity often 
show. 
The mineral used was in all cases a reddish chert 
of various shades, found abundantly in the shape of 
rounded stones upon the beach. The chippings are 
irregular flakes, amounting in certain localities to 
what might readily fill a bushel basket; and search 
nearly always reveals some broken and unfinished 
arrow-points of the same mineral. The successive 
stages occur, from the rough chert flake to the com- 
pleted implement; the most common being simply a 
- half-arrow point, presenting a fracture across the 
shorter diameter: more rarely, specimens show a lon- 
continuously for a number of miles south, there are 
exposed intervals where the frequent violence of 
the lake-winds does not permit the usual growth of 
vegetation. These places are often scattered with 
gitudinal fracture. 
indicates that occasionally, after an implement had 
assumed nearly the desired shape, an unskilful stroke 
split it; and the pieces were allowed to fall with the 
The ,abundance of specimens 
