1892. | NEW YORK ACADEMY OF SCIENCES. 143 
Near the southwestern end of Skunnemunk Mountain, about two 
and one-half miles north-northwest of Monroe, and one-fourth mile 
southwest of the Seven Springs Mountain House, are the Davidson 
quarries. The lower quarry is approximately 290’ higher than the 
Cooley quarry, or about 750’ A. T. An excavation has been made 
in the ledge at a place just north of the highway, and the eastern 
wall of the quarry is ten feet high. Some bluish-gray flagging- 
stone has been taken out, but a considerable part of the quarry is 
composed of shaly gray arenaceous layers. At the northeast corner 
are two layers containing fossil plants, which are separated by a 
stratum of the bluish sandstone. The plants are generally in the 
more argillaceous lay ers, although specimens poorly preserved are 
occasionally seen in the coarse, bluish-gray sandstones. In this 
quarry, which may be called the lower Davidson, specimens of 
Psilophyton princeps Dn., Calamites sp., and aérial rootlets of 
Calamites (?) oceur. 
A short distance northeast of the lower quarry and a little higher 
is the Davidson ‘‘ Coal Mine” quarry, from which Professor Martin’s 
plants were collected. The quarry has been opened to a consider- 
able extent, the wall of rock being twenty feet high on the eastern 
side. The dip is apparently to the northeast, but on account of 
false bedding and thinning of the layers it is difficult to determine 
the amount and direction. Considerable bluish-gray flagging-stone 
has been removed from this quarry, and in lithologic characters it 
resembles closely the Hamilton flagging-stone of Ulster and Greene 
counties, New York. 
No fossils were found except plants, and these are quite abundant 
in certain layers of the quarry. The most common species is 
Psilophyton princeps Dn. 
The plants collected by Professor Martin probably came from 
this quarry, and through his kindness the writer has had the 
pleasure of examining a portion of the collection. Specimens of 
the Pstlophyton princeps Dn. from this quarry have been examined 
by Sir J. Wm. Dawson and Professor D. P. Penhallow, and they 
agree with the above identification. From Professor Martin’s col- 
lection, specimens of the Lepidodendron, Calamites, and Dadoxylon 
identified by Dr. J. 8S. Newberry as LZ. gaspianum Dn., C. transi- 
tionis Gopp., and Dadosyton (?)' were submitted to Dr. Dawson. 
Principal Dawson agrees with Dr. Newberry in the identification 
of the Lepidodendron; the Calamites he would call C. radiatus 
Brongn., regarding C. transitionis as a synonym of the preceding, 
and the Dadoxylon he calls the aérial roots of a Calamite or fern. 
The distribution and range of Calamites radiatus Brongn , also 
frequently called Bornia radiata (Brongn.) Sch., and Archexo- 
calamities radiatus, (Brongn.) Stur, including Calamites transi- 
tionis GOpp. as a synonym, are quite extended, and no attempt has 
been made to verify the numerous reported identifications of this 
1 Proc. Lyc. Nat. Hist., N. Y., vol. i, p. 259; and An. Rept. State Geol. 
(New Jersey), for 1884, p. 54. 
