Miscellaneous. 235 
5. Olivine, in small grains and crystals, occurring generally in 
groups imbedded in those of felspar. They are easy to distinguish 
by their form and polarization; and, though fresh and unaltered in 
the interior, they are bounded by a thick band of brown ochreous 
matter, due to decomposition. 
6. Magnetite, in minute grains and small quantity, visible with a 
1-inch objective. 
The order of crystallization appears to have been :—first, magnetite 
and olivine; second, the felspars; third, mica; and last, augite. 
It was remarkable that in a rock of probably Mesozoic age the 
minerals should be so slightly (in most cases not at all) altered. 
MISCELLANEOUS. 
Observations on Siredon lichenoides. By Wrti1am E. Cartin. 
Como Laxe, U.S., is a body of water about two miles and a half 
in circumference. It has no known outlet, but is fed by a stream of 
pure spring-water about two feet wide and a foot deep, which, con- 
tinually running, prevents the lake’s absorption by evaporation. 
The lake is quite shallow, and can be easily waded at almost any 
part, being not more than 10 feet deep in the deepest place that I 
have been able to find. The bottom of the lake is soft, and is 
covered in most places with grass and weeds. ‘The water is strongly 
impregnated with alkali; and a large number of cattle are said to 
have died a number of years ago from drinking it. It is very dis- 
agreeable to the taste. The amount of water varies about 14 inches 
during the year, being highest in the spring, from the melting snow, 
and lowest in theautumn. Thisis the home of the Siredon lichenordes 
(Baird). They never enter the stream of fresh water, preferring the 
alkali water of the lake. They seem to suffer no inconvenience, 
however, if placed in fresh water. I have caught as many as a 
hundred and fifty, and placed them in a cauf, and have never had 
one die from the change. The change to fresh water undoubtedly 
hastens the metamorphosis into the Amblystoma form, as I have 
noticed quite a change in the course of twenty-four hours in indi- 
viduals placed in the cauf, while an equal number kept in the 
alkali water in the boat have shown no change in any of them in 
several days. I have kept six at different times in jars of fresh 
water until they have completed their metamorphosis. JI made no 
systematic note of appearance from day to day; but my observation 
was careful and regular. In two cases the change in external ap- 
pearance was so abrupt that I should have been almost certain that 
another salamander had been substituted for the one in the jar, had 
J not had him so completely under observation that it was impossible. 
The gills had assumed a stubby form about half the length that they 
were the night before; and the gill on the back of the body was nearly 
