J. D: Dana—Taconie Rocks and Stratigraphy. 411 
Mr. S. W. Ford and himself appeared in this Journal for 
April, 1886,* and announced the existence of crinoidal joints, 
and probably a species of Clevocrinus, of Pleurotomaria, and 
Murchisonia ; and made the age to be probably, or perhaps, 
Trenton. The localities then known are the two more southern 
of the four marked by o in a circle on the map, the northern 
of these two being that at the railroad tunnel where the most 
of the specimens were obtained. At the meeting of the Ameri- 
can Association in last August, Professor Dwight made known 
other fossils from a locality two miles north of the tunnel, at Mr. 
Hemminegway’s, including species near Ophileta, one to nearly 
two inches in diameter, others related to Holopea, and numer- 
ous small crinoidal disks. Since then he has discovered, in the 
limestone 500 yards farther north (on the property of Prof. 
Drown) still other kinds, including a brachiopod, a Lntuites, or 
related form, an inch and a quarter across, and Orthocerata 
nearly a foot long and two inches in diameter, remarkable for 
the closeness of their septa, with also Trilobites resembling the 
Bathyuri, and other kinds not yet determined. He has the 
fossils under investigation and will report on them before long. 
The age of the fossils at the last mentioned locality, he regards 
as either Calciferous or Chazy. 
Whatever doubt may exist as to the particular periods to 
which the species collected should be referred, it is beyond 
doubt that all are Lower Silurian in age. Other fossils which 
are decisively Trenton in age, | bave reported as occurring in 
loose masses of limestone in Canaan on the farm of Mr. E. 8. 
Hall, not a mile from the schist of the Taconic range.t The 
masses consist largely of the minutely columnar coral, Solene- 
pora, which occurs in small nodule-like forms and makes a 
limestone that looks like a limestone conglomerate. Along 
with this coral, occur crinoidal stems and other small fossils. 
The rock is nearly identical in species, and in aspect, with the 
Solenopora limestone found far to the southwest at Pleasant 
Valley, within eight miles of Poughkeepsie, and described by 
Professor Dwight. The loose masses are not worn, and this 
favors the view that they are from some underground ledge to 
the northward or northwestward, although none just like it 
occurs there in sight. Mr. Dwight in searching for an outcrop 
of such a Solenopora limestone in Canaan, found similar 
nodules in some of the limestone, but they failed of the 
columnar structure, and he is of the opinion, that the failure 
is due to incipient metamorphism; which is very probably the 
fact; for the first trace of metamorphic change would obliterate 
columns only 1-500th of an incl: in diameter; and specimens 
thus changed he has found to be common near Poughkeepsie. 
.* Thid., p. 248. + This Journal, xxxi, 241, 1886. 
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