102 The American Geologist. August, i904. 
vue, and Corryville horizons bnt is not common until the 
Mount Auburn bed is reached. It occurs in the Mount Au- 
burn bed also in Indiana, but, except in the neighborhood of 
Madison, it appears to be very rare at this upper horizon. In 
Ohio, specimens are known even as far up as the middle of 
the Warren bed. INIany of the gerontic ]\It. Auburn specimens in 
Ohio are characterized by the possession of a remarkably short 
hinge line, resulting in a more globose form for the shell. 
12. Streptelasma, Heterospongia, Beatricea. 
Streptclasiua ritsticnin, or rather the form which passes 
under this name in Ohio and Indiana, occurs at Concord, Ken- 
tucky, at 47 feet and again at 58 feet beneath the base of the 
HeherteUa inscnlpta layer, while Dahnanclla jugosa is found 
in abundance only between 44 and 28 feet beneath this layer. 
Heterospongia, a branching form of unknown affinities, oc- 
curs at Madison eight feet above the base of the Madison 
bed; at Versailles it occurs at the base and also two feet be- 
neath this bed; along Elkhorn creek near Richmond it occurs 
in the Madison bed about 38 feet below the top. A large 
typical specimen of Beatricea nndtilata was found immediate- 
ly above the massive coral layer at the base of the ^Madison bed 
at Madison, Indiana. 
EARTHQUAKES IN SOCORRO, NEW MEXICO. 
By RuFUS M. Bagg, Jr., Socorro, New Mexico. 
Thirty-four earthquake shocks have been felt m Socorro 
during the last three months. Seismographs have therefore 
been constructed in the basement of the New ]\Iexico School 
of Mines for more accurately investigating these phenomena. 
Since this work was done we have had one earthcjuake which 
occurred shortly after midnight on the night of IM'arch 8, 
1904. The first decided shock came at 7: 10 p. m.. January 19, 
shaking doors, rattling windows and swaying objects back and 
forth. It was accompanied by a heavy rumbling sound like 
thunder. Several minor tremors occurred that same night. 
The next marked disturbance was on the 30th of Jan- 
uary at 5 : 25 a. m. On the 21st of February at 11 : 30 p. m. 
another rather sharp earthquake occurred and there were three 
pronounced jars during the night. The last shock was on the 
