26 NEW YORK STATE MUSEUM 



far as Vly mountain. North of this hill it disappears against the 

 slates. The belt is bounded by the slates on the west throughout 

 its entire length. Vly mountain is cut off from the main mass by 

 a transverse fault which has offset the main belt to the west by its 

 own breadth. This fault is occupied by a large swamp, to which the 

 eminence probably owes its name. The mountain is bounded on 

 the east by the slates and on the south by the Fishkill limestones. 

 The latter border the main portion of the belt on the east to its 

 southern extremity. The southern end of the strip is faulted against 

 the slates. 



Mather called this mass a " granite rock " in his description^ and in 

 his section the '' Matteawan granite" (see plate 12, loc. cit.). He 

 separated it from the gneiss of Bald hill, but apparently regarded 

 it as a part of the Highlands. 



E. Emmons- cited this rock as an example of the uplift of in- 

 ferior rocks into the newer ones. He described the relations at Glen- 

 ham. His section is given herewith. • 



Fig. 10 a, slate; b, granite (of Glenham belt) ; c, limestone; e, Fishkill mountain. (After Emmons) 



Hall and Logan, in 1864, called it an ' altered sandstone," ^ J. D. 

 Dana, in 1879,* referred to it as " bastard granite " and described it 

 as one of the " stratified deposits as is shown by its conformable 

 position and by its taking the color of the slate near its junction." 

 The Highlands were the source. 



Smock in 1886^^ expressed doubts of its being stratified. He 

 placed it with the Highlands, though the prevailing types of rock 

 were unlike the characteristic varieties of the Fishkill mountains. 



In the southern portion of the Glenham belt the prevailing rock 

 is a rnassive variety of the granitic gneiss. This is exposed for 

 some depth in the railroad cut west of Glenham station. It is of 

 dark green color and shows scarcely any tendency to foliation. 

 South of this cut and for some distance to the north, surface out- 

 crops are almost always of this type of rock, though varying in 



1 Geology of the First District, 1843, p. 437. 



2 Agriculture of New York, Part IV, 1846, p. 103. 

 ^ Amer, Jour. Sci., Ser. 2, 39 -.gy. 



*Amer. Jour. Sci., Ser. 3, 27:386. 



^ Thirty-ninth Ann. Rep't N. Y. State Museum, p. 176. 



