Key points are not available for this paper at this time.
Peter J. Mehringer, Jr., Stephen F. Arno, Kenneth L. Petersen, Postglacial History of Lost Trail Pass Bog, Bitterroot Mountains, Montana, Arctic and Alpine Research, Vol. 9, No. 4 (Nov., 1977), pp. 345-368
Mehringer et al. (Tue,) studied this question.