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New Localities of Agate, &c. 135 
small pieces, is as perfect in its characters as the chalcedony 
of the Feroe Islands. It is of a delicate gray, translucent, 
mamillary, botryoidal, stalactitical, or impressed by crystals 
of quartz, which have usually fallen out; sometimes these 
crystals incrust the chalcedony. 
Agates, also, are found in considerable numbers, both imbed- 
ded and loose. They usually consist of bands of chalcedony 
and quartz, and sometimes of the latter only, variously striped 
or spotted, or interlaced with jasper, carnelian, and cacho- 
long. 
The form of the imbedded agates at East-Haven is com- 
monly ovoidal, or. egg-shaped, and frequently it is conical. 
Some portions .of pure chalcedony occur, which are s 
like a long, slender carrot, or parsnip, and the situation of the 
latter in the ground would exactly represent that of the chal- 
cedony or agate in the rock. 
The imbedded masses are frequently altogether quartz, and 
then they are most commonly geodes or hollow balls lined with 
crystals, commonly very perfect and brilliant, although rare- 
ly large. These crystals are commonly transparent and co- 
lourless—but they exhibit also most of the varieties of co- 
lour which quartz, assumes—the amethyst—the smoky—yel- 
low, &c., and occasional y they are tipped and spotted with red 
Jasper, 
The spontaneous decay of these trap rocks causes many 
Specimens to be found among their ruins, and many more are 
imbedded in the solid rock; but the industry of successive 
classes from the neigbouring college, issuing from Col. Gibbs’s 
cabinet, has now made specimens more scarce. 
Woodbury. Twenty-four miles from New-Haven, N. W. 
In a geological sketch of parts of the counties of New- 
Haven and Litchfield, which may appear in a future Number, 
it will be Seen that prehnite, stilbite, and agate, are found at 
codbury, in the little basin of secondary greenstone which 
“xists there; the prehnite is abundant—it is not known 
Whether the agates are so, although it is asserted to be the 
_ fact: the stilbite was not observed to be abundant, although it 
Was well characterized. 
