1887] Mineralogy and Petrography. 271 
inway outcrop is, however, much the richer in fossils, of which 
ste following have already been Keone : 
. Crinoidal fragments in vast number: 
z Fragments of lamellibranchs, pets of the genus Lyro- 
desma. 
= Gasteropods of several genera and species. One of these is 
‘diameter, and have six or seven whorls. They look exceedingly 
like Ophileta, but may prove on careful examination to be Heli- 
cotoma or Pleurotomaria. 
4. A single genal spine of a small trilobite 
There were open also, large calcareous slates, whose precise 
nature is not evi 
The general ad of these organic remains indicates very 
decidedly the post-Cambrian origin of the strata; while, in spite 
of the Ophileta-like appearance of some of the Gas asteropods, the 
presumption is strong that they belong to the Trenton epoch. 
Nore.—Subsequently to the presentation of the above paper, 
the continuation of these investigations at Canaan developed 
yet more important facts. In a limestone ledge on the Hemin- 
way farm, lying a little east of the fossiliferous outcrop above 
described, indications of Orthocerata were noticed; on following 
this outcrop northward a few hundred feet into the farm owned 
by Professor Charles Drown, quite a number of very interesting 
Orthocerata were discovered. These are finely preserved and dis- 
tinctly characterized, showing admirably the septa and siphons. 
One of these is very nearly one foot long, and its shell is quite 
cylindrical, since the taper is exceedingly gentle. The septa in^ 
all are quite frequent, about fifteen to twenty to the inch. A well 
defined lituite was also found here. 
ese Orthoceratites are of the same general m as those 
occurring at Rockdale, near Poughkeepsie, N. Y., which from 
their character, and from their associate fossils, I consider as 
belonging to the horizon at present known as the Calciferous. 
This, and the Trenton, therefore, appear to be associate com- 
ponents of the Canaan limestones —Wm. B. Dwight. 
MINERALOGY AND .PETROGRAPHY. 
Volcanic Bombs.—In view of the fact that the volcanic bombs 
of Monte Somma present such a large variety of beautifully crys- 
tallized minerals in druses, and further, that in the case of the 
limestone bombs these minerals may well be supposed to owe 
their origin to the action of the hot lavas on pieces of limestone 
torn from the walls of the vent through which the lavas reached 
z Edited by Dr. W. S. Bayzey, Madison, Wis. 
