STR UCTURE OF THE MO UNT WA SHING TON MA SS. 7 1 9 



through which runs the Central New England and Western Rail- 

 road. On the northwest Mt. Washington is merged into the nar- 

 row ridge of the Taconics, which extends northward into Vermont. 

 The name Mt. Washington, however, applies properly to all of 

 the range lying south of the South Egremont-Hillsdale turnpike. 

 The regular elliptical contour of the mass is broken on the north- 

 east by two deep embayments, the eastern one containing Fenton 

 Brook, and the western, which is knee-shaped, being occupied by 

 Sky Farm Brook. The regularity of contour is further interrupted 

 by an outjutting spur on the west side, known as Cook's Hill. 

 South of the topographical break which limits the mountain in 

 the neighborhood of Ore Hill, the range of the Taconics pur- 

 sues a more interrupted course, the hills becoming smaller and 

 spreading out considerably. 



Previous Work within the Area. — As the aim of this paper is 

 mainly to deal with the problem of mountain structure, no men- 

 tion will be made of the part which the area has played in the 

 " Taconic Controversy," except as structural facts may be brought 

 out by it. The boundary between the basement limestone and 

 the schistose rock of the mountain was roughly located by Hitch- 

 cock 1 for the northern portion, and by Percival 2 for all but the- 

 extreme northern portion of the mountain. The former gives 

 (Plate 55 E of the work cited) a section across Mt. Washington, 

 in which the schist and limestone of the east base of Mt. Everett 

 are shown dipping at a steep angle east. Mather 3 gives two sec- 

 tions across the Taconic Range in the vicinity of Mt. Washing- 

 ton. One of these (loc. cit. PI. XIV, Fig. i) is from Hillsdale, 

 N. Y. to Egremont, Mass., and passes a little to the north of Mt. 

 Washington ; the other (PI. XVI, Fig. 3) is from Hudson, N. Y., 

 to the southwest corner of Canaan, Ct. The latter crosses the 

 mountain in a northwest-southeast direction and exhibits a syn- 

 clinal structure. 4 



"Geol. of Mass., Edward Hitchcock, Amherst and Northampton, 1841, Frontis- 

 piece Map. 



2 Rept. on the Geol. of the State of Connecticut, J. H. Percival, New Haven, 1842, 

 Frontispiece Map. 



3 Natural History of New York, pt. iv. Geology, pt. i. 1845. 



4 In his list of dip and strike observations Mather includes several from the Mt. 

 Washington area (pp. 612-613). 



