UNSTRATIFIED PRIMARY ROCKS. 225 
and finished in the most perfect manner, with carv- 
ed capitals, and cost 4000 dollars each. 
That variety of granite that contains hornblende 
in the place of the mica, and known under the name 
of syenite^* is found in alDundance in the same neigh- 
bourhood with the granites here mentioned, and is 
itself almost as largely wrought as the true granite, 
or triple combination of quartz^ feldspar^ and mica* 
The Astor House in the city of New- York is built of 
this stone ; and from the same quarry are obtained 
a large portion of the doorposts, window-sills, cap- 
stones, and foundation pillars of the buildings now 
being erected in that city. The Washington Bank 
in Boston, and the Bunker Hill Monument, are built 
also of syenite. 
Por'phyry, syenitic porphyry^ and porphyritic green-- 
stone, abound in various places adjacent to the coast 
of New-England, especially to the north and south 
of Boston. Near Lynn the porphyry assumes all 
the dark purple and other tints, with the fine polish 
of the best antique varieties ; and when ornamental 
architecture shall be more cultivated in this coun- 
try, this rock will doubtless be considered as of in- 
estimable value. 
^Syenitic porphyry, or a syenite with imbedded crys- 
tals of feldspar, occurs plentifully in fine specimens 
near Cape Ann ; and a rock splendidly ornamented, 
consisting of a fine greenstone paste, with dissem- 
inated crystals of greenish feldspar, and sometimes 
called porphyritic greenstone, is found in large veins 
traversing syenite not far from the same headland. 
* From Sienna, in Upper Egypt, whence were obtained the 
well-known Egyptian monuments, such as Cleopatra's Needle, 
Pompey's Pillar, Trajan's Pillar in Rome, &c. Many writers 
describe the syenite as consisting of feldspar and hornblende. 
The rock from Sienna is now ascertained to be a red granite^ 
containing black mica and a small portion of hornblende. 
