S TR UC TURE OF THE MO UNT WA SHING TON MA SS. 7 2 1 



the mountain as composed of two close^pressed synclinals in the 



Mt. Washington plateau with steep easterly inclined axes, and 



that these synclinals are synclinals of slate riding over a single 



synclinal of limestone. 



In 1877, in a paper entitled, " On the Relations of the Geology 



of Vermont to that of Berkshire," 1 he adds, referring to the 



anticlinals of limestone between the three northern spurs of the 



mountain : 



"It has not been possible to follow these subordinate anticlinals southward, 

 because the limestone is not continued far in that direction, and the summit of the 

 mountain is under soil and cultivated farms. But yet the fact of flexure at the north 

 end is strong reason for believing fhat similar flexures, if not the same continued, char- 

 acterize the_ whole length from north to south of the mountain-mass, such a slate easily 

 flexing under uplifting lateral pressure. This is further sustained by observations 

 proving that other subordinate anticlinals exist on the western slope of the mountain, 

 in the vicinity of Copake Furnace. Close to the western foot there are two nearly par- 

 allel limestone areas, parallel to the axis of the range. The inner (or more eastern) 

 one is about a mile long, and the other about half a mile. They are separated from 

 one another by a thin belt of hydromica slate, and the same slate exists on the other 

 sides. The dip of the beds of limestone and slate is to the eastward 50 °, the strike 

 averaging N. 15 ° E. (true). They are evidently registers of local folds — anticlinal and 

 synclinal, the former bringing up the limestone." 



In the paper "On the Hudson River Age of the Taconic 

 Schists," 2 Professor Dana has put on record new observations 

 showing the synclinal character of the mountain (I.e., p. 376) 

 and printed a map including a part of Mt. Washington (p. 379) 3 . 



Another paper, "On the Southward Ending of a Great Syn- 

 clinal in the Taconic Range," 4 is specially devoted to a consider- 

 ation of the structure of Mt. Washington, and contains a map of 

 the southern portion of the mountain on a scale of eight-tenths 

 of an inch to the mile. Professor Dana's earlier conclusions as 

 to the synclinal character of the mountain, had been largely drawn 

 from observations made in Massachusetts. The conclusion that 

 the synclinal character of the northern portion of the mountain 

 is continued to the southern extremity, he drew from the fact 



1 Am. Jour. Sci., 3rd ser., vol. xiv., pp. 262-263. 



2 Am. Jour. Sci., 3d ser., vol. xvii., pp. 375-378 (May, 1879). 



( 3 Cf. also ibidem, Supplement to vol. 18, for dip and strike observations). 

 4 Ibidem, vol. xxviii., p. 268 (Oct., 1884). 



