238 MISS MARIETTA PALLIS ON THE 
Sulina: the mean height of the spring floods is 6°05 m. (about 19 feet 
10 inches) above the minimum water-level of the Danube at that point (zero 
on the local river flood.gauges). At Tulcea, at the apex of the delta, 
72 kilometres (about 45 miles) from Sulina, it is 2:93 m. (about 9 feet 
7 inches), and at Sulina itself 0-49 m. (about 1 foot 7 inches), with a 
maximum height of 0-81 m.* (about 2 feet 8 inches). The height of 
minimum water-level at these three places is, respectively, 42:13 m. 
(about 138 feet) above zero of the Black беа T, 0°39 m. (about 1 foot 
3 inches), and zero. Thus it will be seen that in the upper course of the 
river the rise of water is very much greater than in the delta. 
With the comparatively low floods which prevail in the delta is connected 
the eomparatively small amount of sediment carried into the Balta itself, 
that is to say beyond the immediate vicinity of the river-channels, in conse- 
quence of which the waters of the Balta remain dark and clear ў. It is the 
small amount of inorganic sediment deposited in the interior of the delta 
that is apparently the factor which practically limits the distribution of Plav 
to that region as a whole ; outside it Plav is merely in an incipient stage 
(see however, р. 245). 
The pathway of the floods depends upon their magnitude in relation 
to the physiographie features of flood-plain and delta interposed in their 
way. Thus, if the flood be small or in an early stage of its rising, the 
waters pass inland laterally along the numerous gérlas which гаш у 
through the Balta and often directly connect the Balta-lakes with the river. 
If, however, the flood be great, the waters do not remain confined to 
the channels but progressively overtop the physiographical obstacles (which 
they themselves for the most part have raised), such as embankments, low 
grinds, and the shoals which block the water-channels at their entrance to 
lake at one end and river at the other, remodel some, sweep away others, 
and finally mount over all but the highest eminences in the Balta $. Circu- 
lation in the Balta does not, however, proceed during flood-time only, but is 
practically continuous either from river to Balta or vice versa. The 
* No official water-levels are taken in the Balta of the delta itself. In the autumn of 
1913, however, when I was at the Kirhana of Rosulet, I daily noted the rise of the waters 
from about the time when they began to rise, September 6th, to October 5rd, when they 
ceased to rise. That autumn they reached a height of about 0'6 m. (about 2 feet). 
* Zero of the Black Sea is low-water-level of the Black Sea, and is 4:88 feet (1:46 m.) 
below the bench-mark which was established in 1857 at the base of the large lighthouse 
of Sulina. 
[ The contrast between the Danube waters and the waters of the Balta is to be seen 
plainly on the south side of the Danube at Sulina, where a Balta stream issues. For a 
short distance the waters of this stream do not mingle with the grey sediment-laden waters 
of the Danube, but remain brown, clear, and distinct. 
$ The large grinds of Letei and Caraorman (see map) in the delta are never flooded. 
