METAMORPHIC ROCKS. 
465 
II. METAMORPHIC ROCKS OF THE HIGHLANDS, AND OF SARATOGA 
AND WASHINGTON COUNTIES. 
The limestones are the rocks in which the metamorphic action is most distinctly traceable, 
and to these the discussion will be mostly confined. 
They are generally coarse-grained crystalline limestones, of a white color, and sometimes of 
a flesh-red color, embracing a great variety of crystallized minerals. Plumbago in hexagonal 
scales, brucite or chondrodite, and spinelle, are almost constantly associated, and very fre¬ 
quently augite of several varieties, sphene, mica, amphibole several varieties, serpentine, 
diallage, phosphate of lime, and a great variety of minerals which will be mentioned in the 
proper place. 
“ In regard to the rarer minerals found in the white limestone group in the northern and 
southern parts of the State, there is a similarity; while there are, it is true, some points of 
difference. Serpentine of various shades, and often assuming a semi-crystalline form, is 
equally common in both, together with occasional crystals of mica, blades of plumbago, etc. 
There are also to be found in them hornblende in all its varieties, pyroxene, scapolite, phos¬ 
phate of lime, zircon, sphene, tourmaline, garnet, brucite and spinelle. The two last named 
minerals, however, have heretofore been found in much less abundance in the north than in 
the south. Orange county is particularly rich in localities of these interesting and elsewhere 
rare minerals.”* 
This limestone is the same in character as that described by Prof. Emmons in the Second 
Annual Geological Report of New-York, 1838, pp. 196, 205, as primary limestone, and like 
that, is associated with similar rocks, is not generally stratified, is frequently intertruded among 
plutonic rocks, and has plutonic rocks intertruded as veins and beds through and between 
parts of its mass. 
In Orange county (New-York), and Sussex county (New-Jersey), all the changes from the 
grey and blue limestones (Mohawk limestone and Calciferous sandstone of the New-York 
Reports, and Formation No, 2 of the Pennsylvania Survey), can be distinctly traced into the 
perfectly crystallized limestone, containing the various crystallized minerals ; so that it is be¬ 
lieved that most of those who will examine the rocks thoroughly, will admit that they are 
metamorphic. 
I spent about two weeks examining the limestone region in Warwick, in 1828 and 1838. 
Unfortunately, the notes made of particular localities have been lost; so that I cannot go into 
that detail of personal observations, with references to particular localities, with drawings and 
diagrams for illustration, that I could wish. I can only state general results, and details 
drawn from the published observations of others. Prof. H. D. Rodgers and Prof. C. U. 
Shepard have described these rocks as they occur near Pochunk mountain, Mount Adam, 
* Prof. Beck’s comparison in the Fourth Annual Geological Report of New-York, 1840, p. 50. 
Geol. 1st Dist. 59 
