TOPOGRAPHY OF THE HARBOR 9 
tape in the manner noted for measuring the boundary of the harbor. When the 
position of plants or tide-limits had to be determined in parts of the harbor 
where, because of water or a muddy bottom, the rod or tape could not be used, 
it was necessary to estimate distances within each 200-foot square. This was 
done by setting temporary stakes at the nearest points in the nearest north-and- 
south, and east-and-west range-lines, and then, after rowing away from these to 
the point to be located, estimating the distance in boat-lengths, and converting 
it into feet. The accuracy of the estimate made was considerably increased by 
making duplicate estimates, usually from range-lines on opposite sides of the 
point to be determined. The error still present in any of these estimates is 
small in proportion to the magnitude of the distances measured. 
The procedure in determining the outlines of the areas occupied by Zostera 
marina may serve as an example of the mode of measuring distances within 
each 200-foot square. Starting from one end of the harbor, on a quiet day, 
with half tide and clear water, the boat was kept along one longitudinal 
range-line from end to end of the harbor. The points at which Zostera was 
first encountered (in a density of 10 or more shoots per square yard), at the 
south end of the harbor, and the points at which it disappeared at the north 
end, were noted. The distances of these from the nearest east-and-west range- 
line, and so from the zero-point, were then estimated. After each longitudinal 
range-line had been followed in this way, the boat was rowed along each 
transverse range-line, and the distance east or west of zero of its intersection 
with the boundary of the Zostera was noted. Connecting up the two series of 
points thus located tended to reduce considerably the error that might occur if 
the intersection of the Zostera boundary with one series of range-lines only 
had been determined. 
2. TOPOGRAPHY OF THE HARBOR; ITS SIZE, DEPTH, CHARACTER OF 
BOTTOM AND SHORES. 
The deep, narrow valley occupied by Cold Spring Harbor has been cut out 
from the mass of gravelly morainal deposit, which makes up this part of Long 
Island, chiefly by one considerable fresh-water stream. The elevation of this 
terminal moraine along the sides of the harbor is 50 to 225 feet above sea-level. 
The nearly flat bottom of that part of the valley in which the Inner Harbor 
lies is just covered at high water, while more than half of it is left bare at low 
water. 
- The upper, or south, end of the valley is occupied by a fresh-water stream, with 
a flow of something over 100 cubic feet per minute. ‘’his main stream, which 
we shall speak of as the “ Creek,” enters the harbor through a culvert under the 
highway, at 580 south by 820 east. A second smaller stream, largely of artesian 
water, coming from the pools of the New York State Fish Hatchery, enters the 
harbor from under the same highway, at a point 100 feet west of the main 
stream or Creek. A third stream, also small, is fed chiefly by springs 200 feet 
or so south of the highway, and it enters the harbor about 70 feet east of the 
creek. 
Beginning at a point about 350 feet above the previously mentioned culvert, 
the main stream is dammed at three points to form large ponds. Each of 
these ponds is bordered, especially at the southern or upper end, by a densely 
