434 REPORT ON NATIONAL MUSEUM, 188G. 



Meriden, in Connecticut ; the Palisades along.the Hudson River, in New 

 York j Bergen Hill and other elevations in New Jersey. 



a In Nova Scotia trap ridges skirt the whole red-sandstone region and 

 face directly the Bay of Fundy ; Cape Blomidon, noted for its zeolitic 

 minerals, lies at its northern extremity on the Bay of Mines. 



" In Connecticut the ridges and dikes are extremely numerous, show- 

 ing a vast amount of igneous action. * * * They commence near 

 Long Island Sound, at New Haven, where they form some bold emi- 

 nences, and extend through the State and nearly to the northern bound- 

 ary of Massachusetts. Mounts Holyoke and Tom are in the system. 

 The general course is parallel to that of the Green Mountains. 



"Although the greater part of the dikes is confined to the sandstone 

 regions, there are a few outside, intersecting the crystalline rocks and 

 following the same direction, and part, at least, of the same system. 



"Even the little Southbury Triassic region, lying isolated in western 

 Connecticut, has a large number of trap ridges, and such a group of 

 them as occurs nowhere else in New England outside of the Triassic. 

 Their direction and positions in overlapping series are the same as in 

 the Connecticut valley. 



"The trap usually forms hills with a bold columnar or front and slop- 

 ing back. When nearly north and south in direction the bold front is to 

 the westward in the Connecticut Valley, and to the eastward in New 

 Jersey. It has come up through fissures in the sandstone, which varied 

 from a few inches to 300 feet or more in breadth. In many cases it has 

 made its way out by opening the layers of sandstone, and in such cases 

 it stands with a bold front, facing in the direction toward which it thus 

 ascended." 



Connecticut. — The extensive diabase outcrops noted above as occurring 

 at East and West Eocks, north of New Haven in this State, are quarried 

 for foundation walls and for paving purposes in the near vicinity. The 

 rock is too dull in color for ornamental work. 



Maine. — Diabase is quarried at three localities in this State, Addison, 

 Vinalhaven, and Tenant's Harbor. At Addison the rock occurs in ex- 

 tensive outcrops close by the water's edge. Single blocks 06 by 10 by 

 20 feet have been moved in the quarries, and natural blocks 90 by 10 by 

 J 5 feet occur. The chief defects in the stone are said to be the so-called 

 " knots," which consist of irregular patches of coarse feldspar and dark 

 crystals of hornblende. There are also occasional seams, causing the 

 rock to split unfavorably. The rock is moderately fine-grained, very 

 dark gray, sometimes almost black or spotted black and white on a 

 polished surface and of a fine appearance. It has been used in the walls 

 inclosing the Capitol grounds at Washington, in the construction of a 

 bank at Montreal, and is quite generally used for monuments in Boston, 

 New York, Brooklyn, Washington, Montreal, and Quebec. The Vinal 

 haven diabase is less extensively worked on account of its hardness 

 It is of finer grain than the A.ddison stone aud uniformly dark-gray ^ 



