164 TRANSACTIONS OF THE [APR. 16, 
DATA RELATING TO THE MISSISSIPPI RIVER. 
The river reached a lower stage during the low-water period 
of 1887 than for several years, excepting at New Orleans, where 
low-water stage was relatively and exceptionally high. 
The Chief Signal Officer U. S. A. has furnished me with the 
following data, viz.: 
At Vicksburg, the mean stage for November, 1887, ‘‘ was 
minus 3.0 feet,” being ‘4.2 feet lower” than the mean for 
November, 1886. 
Notwithstanding this remarkably low stage of the river, the 
mean stage at New Orleans during November, 1887, was ‘‘ plus 
2.0 feet,” being ‘‘ one-tenth higher” than the mean for Novem- 
ber, 1886. 
The lowest water at New Orleans during November, 1887, was 
three-tenths of a foot higher than the lowest stage in November, 
1886. 
The Chief Signal Officer states, in his letter to me of April 9th, 
1888, as follows: ‘‘ There is shown to be a relatively high stage 
of water at New Orleans. ‘The cause of this may be due to the 
fact that there is a gradual obstruction to flow, owing to accumu- 
lations of some sort in the vicinity of New Orleans. ‘The cause 
is hardly to be looked for in the gauge, yet it is possible.” 
Assuming the gauge to be correct, the relatively high stage at 
New Orleans would show a deterioration in the channel of the 
river. The cause of this deterioration is found in the artificial 
works that have been placed in the river, in conjunction with 
the deposition of sedimentary material consequent upon these 
works; these together form the obstruction and heap up the 
waters of the river. The artificial works referred to are at New 
Orleans, and in the passes. 
Mr. B. B. CHAMBERLIN spoke of some interesting quartz 
crystals from New York Island. Crystals of smoky-quartz were 
found mounted on pedestals of milky-quartz. The former were 
one-third inch in diameter, doubly terminated with very short 
prismatic faces. Of larger size were prisms of limpid quartz 
with caps of amethyst, some of which are removable. 
Dr. OLiveER P. Hupsarp referred to some large quartz 
