LOCALITIES. 557 



bed is N. E. and S. W., and the dip is 52 S. W. The rock is mostly white. It contains many veins of 

 micaceous iron ore. The limestone is of the same quality at Craigue's quarry. Connected with it there are 

 two trap dikes made up of concretionary masses which cross the strata, and are so inclined as to form an 

 anticlinal with each other. One dips southerly 59, and the other northerly at about the same angle run- 

 ning N. 60 E. The removal of the limestone shows these dikes beautifully. There are several small beds 

 of limestone north of Amsden's mill in the region called Greenbush. One bed is on the west side of Little 

 Ascutney. Probably the valley west of this mountain originated in the easily decomposing character of 

 the rock. 



The largest deposit of dolomite in the azoic rocks is in Plymouth. For a proper idea of its distribution 

 we refer to Plate XVIII. It probably commences in Ludlow, and extends into Sherburne, along the great 

 valley of Black River, and Otta Quechee River. It is said to extend into Bridgewater. We suspect that 

 it may connect with the large bed of limestone in Mendon, and there is a possibility that this limestone is 

 a repetition of the Eolian limestone upon the west side of the Green Mountain anticlinal. Specimens of 

 this limestone which have been analyzed prove it to be a dolomite. Some beds of it make an excellent marble, 

 as the brecciated marble east of Plymouth Pond belonging to the Neshobe Company, will show. It is 

 brecciated a little like the Winooski marble. Measured in several places in the north and middle parts of 

 the town the strike of this limestone is N. 10 W., and the dip 45 E. The invariable dip is to the east. 

 One of the most interesting stratigraphical features of this limestone is its interstratification with quartz 

 rock and talcose schist in the south part of the town. Not less interesting is its development upon the 

 east side of a great range of mountains (Mt. Tom), running southerly almost parallel to the principal belt. 

 Micaceous oxyd of iron is common in the dolomite in veins. Probably from this ore, and the iron in the 

 composition of the dolomite, the tertiary hematites in the south part of the town were derived. The color 

 of the Plymouth dolomite varies from white and reddish-white to a dark bluish or dun color. Other facts 

 respecting this limestone will be given in the Geology of Plymouth. 



In the northeast part of Mendon, upon the west side of the summit of the Green Mountains, there . is 

 an unknown area underlaid by white limestone. As bowlders of it are scattered over a large area, its 

 extent is probably considerable. And we have found ledges of it at least a mile distant from each other. 

 One ledge of limestone shows a dip of 25 N., and a direction of east and west. Another set of strata run 

 N. 10 E., and dip 25 E. This is the more usual position, we suppose. The ledge examined is ten rods 

 wide, and no rocks crop out at the surface within two miles of it. The limestone is white and fetid. It 

 reminds us more of the Eolian limestone than of the azoic. It is said to extend into Sherburne. It is 

 probably a bed in gneiss. 



Half a mile south of the village of Hancock there is a bed of limestone, of large extent. It is not a 

 dolomite, though it contains a little magnesia. It is composed of carbonate of lime 90.3, carbonate of 

 magnesia 6.9, oxyd of iron a trace, silica 2.8. The silica occurs in grains. 



In the middle of Granville, along the west side of the valley, a bed of limestone extends for one or two 

 miles. It is probably connected with a bed in the north part of the town on the land of William C. Chaf- 

 fee, Esq. There are two varieties of the limestone here. One is white and granular ; the other is dark-blue 

 and compact. The former upon analysis is found to be composed, of carbonate of lime 89.741, carbonate 

 of magnesia 4.264, oxyd of iron and alumina 2.420, silica 4.875. It occurs in two beds of unknown 

 width. About ten feet in width of one of them was exposed to view. It dips 63 E. and runs N. 20 E. 



There is a large bed of dolomite in Rochester, the details of which are not before us. In the west part 

 of the town we found occasional layers of dolomite, as also in the north part of Bethel, but they could not 

 be designated as large beds. 



There are two quarries, called marble quarries, in the northwest part of Moretown, which belong to the 

 same belt of rock. The most northern is ten or twelve feet wide. It is both white and clouded, and the 

 strata are compact, somewhat in the manner of marble. West of it there is another bed still smaller. Its 

 strike is N. 3 E. It stands upon its edges. 



There is said to be a bed of limestone in Duxbury. 



