IA : NEW YORK STATE MUSEUM 
namely, that the Cortlandt series of rocks were metamorphosed 
limestones. 
Dana *’ subsequently revised his opinion of the origin of some of 
these rocks, however. New and better exposures in a cut made 
through the rocks at Stony Point for the West Shore Railroad, then 
under construction, afforded opportunity for a more critical study. 
After inspecting the rocks thus exposed, Dana conceded that while 
the facts proved the hornblende rock and the related augite rock to 
be eruptive, they threw no new light on the origin of the soda 
granite. He had in the meantime completed his work on the lime- 
stones of Westchester county and after taking into consideration all 
the facts as they appealed to him, and which are so excellentiy pre- 
sented in the series of papers mentioned, felt justified in making the 
following statements (op. cit. 20, p. 371.): “ The limestones and 
adjoining schists of Westchester county: (1) are one in series and 
system of disturbance (this observation is correct, but his age-corre- 
lation is incorrect), (2) are probably part of the Green Mountain 
system, (3) are younger than the Highland Archean, (4) are prob- 
ably of the age of the Lower Silurian.” 
In support of the above statements Dana offered as evidence the 
condition and position of the slightly crystalline limestone and con- 
tiguous fine sericitic phyllite (Annsville phyllite) at the mouth of, 
and along Peekskill creek; he remarked that both rocks are like the 
rocks of Dutchess county (Hudson River slates and Wappinger 
limestone), and unlike anything else found in the “ Highland 
Archean,” but he failed to recognize the fact that while the limestone 
and phyllite at Annsville are in truth Cambro-Ordovician sediments, 
they represent an infaulted block of these sediments and should not 
have been connected with the highly metamorphosed crystalline 
limestone and schists of the Highlands area at all. Dana thus 
confirmed Mather’s earlier opinion in regard to the age of the 
crystalline limestones and the schists of the Highlands area in 
southeastern New York, the weight of his authority inducing other 
workers in the same field to accept his views ** which were not 
questioned until Berkey * in 1907 first called attention to the 
infaulted block of Cambro-Ordovician sediments in the Highlands 
complex in the vicinity of Peekskill, and suggested that field relations 
17 Dana, James D. Note on the Cortlandt and ue Point Hornblendic 
and Augitic Rock. Am. Jour. Sci., 3d ser., 28: 384-86. 1884. 
18 See especially New York City Folio 83, WNSWGHS: 
19 Berkey. C. P. Structural and Stratigraphic Features of the Basal Gneisses 
of the Highlands. N. Y. State Mus. Bul. 107. 1907. 
