SHIFTING OF THE CONTINENTAL DIVIDE AT BUTTE 587 



ORIGIN OF LEACHED PHOSPHATE 

 BY C. H. HITCHCOCK 



PETROGRAPHY OF THE AMPHIBOLITE, SERPENTINE, AND ASSOCIATED ASBESTOS 

 DEPOSITS OF BELVIDERE MOUNTAIN. VERMONT 



BY V. F. MARSTERS 



The paper is printed as pages 419-446 of this volume. 



SHIFTING OF THE CONTINENTAL DIVIDE AT BUTTE, MONTANA 

 BY W. H. WEK1) 



[Abstract] 



This paper discusses the faulting and tilting of the fault blocks immediately east 

 of Butte, Montana, with the accompanying reversal of drainage, filling of broad 

 and deep valleys by imponded wash and debris, the formation of the so-called 

 Tertiary lake deposits, and the change of the groundwater level, affecting the min- 

 eral deposits of Butte. The peculiar physiographic features near Butte are dis- 

 cussed, namely, the fault scarp of the east ridge, the distributed faulting making 

 zones of easy erosion and leaving the harder, unbroken granite as foothill knobs 

 in peculiar prominence. The great flat at Butte is shown to be an old valley leveled 

 by the wash of torrents, and the peculiar mountain basin known as Elk park, which 

 now drains into the Atlantic, is shown to be the headwater portion of a valley 

 whose eastern end has been faulted and tilted northward. The facts presented in 

 this rather limited area apply to the remarkable series of north and south valleys 

 rilled with alluvial and supposedly lacustrine sediments found throughout the 

 mountainous region of Montana. 



NANTUCKET SHORELINES. Ill, MUSKEG AT 

 BY F. P. GULLIVER 



RELATION OF LAKE WHITTLESEY TO THE ARKONA BEACHES 

 BY FRANK B. TAYLOR 



I Abstract] 



Recent investigations in southeastern Michigan have disclosed a new and some- 

 what peculiar episode in the Great Lake history. Lake Maumee was the earliest 

 and highest of the glacial lakes in the Erie-Huron basin. It is found that when 

 this lake was drained off the waters fell to the level of the upper beach of lake 

 Arkona, and that at the close of this lake's existence the ice-front readvanced, 

 pushing the point of discharge up the crest of the thumb, thereby closing the 

 earlier outlet and raising the waters to the level of the Belmore beach of lake 

 Whittlesey. In this way the Arkona beaches became submerged, and they 

 remained in that state during the existence of lake Whittlesey. The paper sets 

 forth the facts which show this history. The general relations may be epitomized 

 thus — the Port Huron-Saginaw moraine marks the position of the ice barrier which 



LXXII— Bom,. Qf.oi.. Soc. Am., Vol. 16, 1904 



