Papers read at the British Association at Montreal. 473 



Till in open situations, liable, however, to obscuration hy contortions 

 within the mass. Of twelve experimental attempts made near the 

 watershed of England in East Cumberland, 600-900 feet above the 

 sea, to determine the ice-movement from this structure alone, eight 

 were correct, three indeterminate, and only one misleading. The 

 pressure and movement capable of producing this widespread fluxion- 

 structure seem to have been that of some mass vast and far-spreading 

 — closely investing, slow-moving, and heavily dragging — such as 

 glacier-ice. It needs only to be assumed that the confluent glaciers 

 communicated something of their own movement and structure to 

 the ground-moraine below. 



8. — On the Southward Ending of a great Synclinal in the 

 Taconic Eange, 

 By James D. Dana, LL.D. 

 fT'^HE Taconic Eange, which gave the term "Taconic" to geology, 

 JL lies in Western New England, between Middlebury, in Vermont, 

 on the north, and Salisbury, in Connecticut, on the south. In 

 former papers, published in the " American Journal of Science," the 

 author has shown, first, that the rocks constituting the range vary as 

 we go from north to south, from roofing-slate and hydromica (or 

 sericite) schist to true chloritic and garnetiferous mica- schists ; 

 secondly, that these schists lie mostly in a synclinal or compound 

 synclinal ; thirdly, that the crystalline limestone along the eastern 

 foot is one with that along the western, the limestone passing under 

 the schist as a lower member of the synclinal ; and, fourthly, that 

 since the limestone contains in Vermont (accoi'ding to the discoveries 

 of the Vermont Geological Survey, and also of Mr. A. Wing), and in 

 the State of New York, fossils of the Lower Silurian, ranging from 

 the inferior divisions to the higher, the Taconic schists are probably 

 of the age of the Hudson Kiver group or Llandeilo flags. 



The author's papers further show that while a large part of the 

 Taconic Range has an eastward dip on both the east and west sides, 

 a southern portion about twelve miles long, consisting of Mount 

 Washington in South-western Massachusetts, and its continuation 

 into Salisbury, Connecticut, is a broad tray-shaped synclinal, the 

 dips of the two sides being toward one another, like the sides of an 

 ordinary trough. The width of the broad synclinal between the 

 limestone belt on either side is about five miles. 



As the result of investigation during the last two years, the 

 synclinal character of this Mount Washington part of the Taconic 

 Range is illustrated in the paper by new sections, and by facts 

 connected with the dying out of the great synclinal (or compound 

 synclinal) in the town of Salisbury. 



The mean height of Mount Washington above the sea-level is 

 about 2000 feet, and above the wide limestone region on either side 

 and to the south, about 1250 feet. The synclinal virtually ends 

 along an east and west line through the village of Lakeville, in the 

 town of Salisbury, where a beautiful lake lies within the limestone 



