Part I John Kimball DeLaski -- Biographical sketch -- The manuscript -- Part II The Ancient Great Glacier of North America -- Preface -- The phenomena of boulder drift -- Carver's Harbor -- Research on rocks -- Vinalhaven and North Haven -- Camden Hills and Mount Desert -- Mount Desert to Holden -- Bangor to the Piscataquis Valley -- Mount Katahdin -- The inescapable conclusion - A large glacier -- Evidence from all over North America -- Boulder drift theories -- Objection to iceberg theory continued -- An astronomical theory -- Astronomical theory continued -- Theory of mutable axis of the earth -- Continental upheaval and subsidence -- The changeable relations of land and water -- Supposed cause of the cold period -- Geologic record since the Devonian -- The climate cools -- A glacial time -- Duration of the glacial age -- End of the glacial age -- On the motion of glaciers -- Purpose of the glacier -- Late-glacial cold-water marine shells of Maine and adjacent regions. Dr. John K. DeLaski practiced medicine in the Penobscot Bay region of Maine and, in addition, was a naturalist with keen powers of observation. His study of the landscape led to his conclusion that a thick glacier had overtopped the highest hills, filled all of Penobscot Bay, extended far to the east and west and probably was part of a greater continental glacier. He published these observations and inferences in numerous local newspapers and magazines, as well as the American Journal of Science. His work put him on the "team" of Benjamin Silliman, James D. Dana and Louis Agassiz, all advocates for glaciation as the regional land shaping force as opposed to that of the Biblical Deluge, a major scientific conflict of the day both in North America and Europe. Agassiz and other prominent naturalists incorporated DeLaski's observations into their own presentations, often without giving him credit. Published now for the first time, DeLaski's summary work presents a holistic discussion of the controversy in which he presents his critical observations of surficial geology in Maine, southern New England and New Brunswick, Canada and concludes that these depositional and erosional features must be of glacial origin. All this was done while most "naturalists" still advocated the Biblical Flood to explain the major components of surficial geology in North America and abroad.