NEWER TERTIARY. 235 



base of the Green Mountains. From Stamford through Bennington, as far as Middlebury, it would prob- 

 few, perhaps from denudation. On the east side of the principal ridge of the Green Mountains, are also a 

 few. We will give a list of the towns where some varieties of these substances 'have been found, attaching 

 the height in feet above the ocean where we have ascertained it by the Aneroid Barometer. After giving 

 the list we will notice any circumstances respecting some localities which we deem worthy of attention. 



Stamford, 1140 feet above the ocean. Clarendon. 



East Pownal, 1150. Chittenden. 



Woodford, 720 to 1008. Rutland. 



East Bennington, 653 to 720. Pittsford, 433. 



West Bennington, 720. Brandon, 506. 



East Arlington, 575. Leicester. 



Shaftsbury. Salisbury. 



Sunderland. Middlebury. 



Manchester. Bristol. 



East Dorset, 1116. Monkton. 



Mount Eolus, 1412. Colchester. 



West Dorset, about 1100. Milton. 



South Wallingford, 729. Swanton. 



East side of the Green Mountains. 



Waitsfield. Plymouth, Tyson's Furnace, 1168. 



Reedsboro, Hartwellville, 1875. 



The difficulty of determining the order of arrangement of the different substances and their dip, has 

 already been stated. At East Bennington the order is as follows (as given by C. H. Hitchcock.) 



FIG. 161. 



1 Drift. 



'. Pipe clay with numerous stems of plants. 

 I Gravel. 



Yellow ochrous clay. 



. Clay with nodules of hematite and pyrolusite ; depth not ascertained. Angular frag- 

 ments of hyaline quartz and quartz crystals are common in the clay. 



At Monkton the bed of white clay is 23 feet thick and overlies a bed of gravel. The hematite bed is 

 half a mile distant. 



At Colchester, two miles northeast of Mallett's Bay, is a bed of hematite ; and bowlders of the same, 

 weighing 100 pounds, have been found with ocher a considerable distance from the bed. 



In Chittenden, according to Prof. Adams, the hematite, in a solid bed two or three yards in thickness, 

 lies upon the limestone with the intervention only of a layer of ochre, one or two inches thick, and the 

 ochres and clays above it. 



In Wallingford, we understand Prof. Adams to say, that the clays and ochres underlie the ore. 



In North Dorset is a dike three feet wide, in limestone, whose contents have an ochreous appearance, 

 and are so soft as easily to yield to the knife. They are chiefly lithomarge, which is an hydrous silicate 

 of alumina with but little iron. It is, evidently, a decomposed dike of porphyry, or porphyritic trap, for it 

 still exhibits minute crystals of feldspar, which retain their white color, although thoroughly decomposed. 

 The dike has been opened 150 feet, and it has been traced half a mile. The lithomarge is used for paints. 

 It may have given rise to some ochre, but ought hardly to be regarded as a deposit of hematite. 



In Chittenden, also, there is a vein of manganese, nearly two yards wide, in a loose arenaceous rock, 

 which appears to have been once calcareous, like the calciferous sand rock. 



On the east side of the Green Mountains, only a few localities have yet been found of brown hematite, 

 associated with manganese, white and colored clays, gravel, quartz rock and limestone. That in Plymouth 

 is a very decided case, however. All these substances are here associated, and the formation is most decid- 



