Geology. : 97 
Canaan Mountain is st apparently -abcrip and, while limestones 
appear in the valleys on each side of it, ¢ chiefly of slates, the 
the conglomerates of the Sillery, oaade boulders and angular 
fragments of these are found in the adjacent valleys, ’ the east of this, 
Richmond Mountain, in Massachusetts, presents in its upper portion a 
compact green late passing upward into a harder rock similar to that 
of the summit of Canaan Mountain. To the southward, as far as Hills- 
dale, the sparry mesons of the Quebec group appear in the valleys, 
while the hills are of slate. Proceeding thence westward toward the 
river, only the lower pen of the Quebec tbe are met with, until 
we come upon the rocks of the Hudson River group. 
Washington Mountain is also of slate, flanked by ane t all of the 
Quebec group, and is probably synelinal i in structure. The valley to the 
south of the mountain exhibits limestones, apparently slieeating with 
below “the city of, Haden. The gneiss of the ie Highlands occupies the 
southeast part of Duchess County. 
From Fishkill the explorers proceeded to Coldspring, crossing what 
Mathet called the Mattewan granite, but which they found to be an 
altered sandstone. Soon after this they came upon tlie great gneiss forma- 
tion of the Highlands of the Hudson, which continues beyond Peeks- 
kill. They failed to find the sandstone deseribed by Mather as coming 
out ve this place; nor was anything representing the Potsdam sandstone 
in approaching the Highlands from Fishkill, nor elsewhere 
aein their northern limits. Near to Peekskill, ~ the valley oe the creek, 
was found a low ridge of black slate, supposed to belong to t e Quebee 
te p, and a similar slate was observed a dine the north side of the 
ighland reel not far from the gneiss. The gneiss of the Highlands 
Presents all the aspects and characteristics of — of the Laurentian n sys 
tem, as seen in northern New York and in Can: 
Panther examinations are-necesii ry to jeterhaine the extension to the - 
northeast of the Laurentian rocks of the Highlands, and also the @ suc- 
cent ones of Professor Cook, according to all of whom the gneiss and 
crystalline limestones of Orange County and of New Jersey underlie un- 
comformably the Lower Silurian strata.’—Can. Nat. and Geol. 
See Am. Jo ur. Sci. [2], : xxxii, 208, and also Kitchell’s 2nd Annual report on the 
of Now demey, (1855,) page — d onward. 
Jour. Sct.—Sncoxn Suniss, Vor. XXXIX, No. 115,—Jas., 1865, 
