Letter to Sir Archibald Geikie from Capt Clarence Edward Dutton

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Letter to Sir Archibald Geikie from Capt Clarence Edward Dutton discussing the fossiliferous Upper Cambrian metamorphosed sandstone shales found at Lake Superior and the Grand Canyon. At Lake Superior these beds overlie 1400 feet of unfossiliferous sandstone and shale, interspersed with layers of copper bearing metamorphosed volcanic ash. These are the same as the Huronian metamorphic beds at Lake Huron which are possibly of the Lower Cambrian age due to an unconformity (as identified by Alfred Richard Cecil Selwyn), although this is disputed. He refers to a similar unconformity at the Grand Canyon where Grove Karl Gilbert identified the lower strata as being Cambrian, despite the adjacent strata being Devonian and Silurian, basing his analysis on a Cruziana fossil. Despite the profession's scepticism, this was later proved correct by the discovery of further fossils.

He reports that field work in the Cascade Range has been delayed and he is writing a paper on the Hawiian volcanoes. He regrets that he will be unable to attend the Association's meeting in Montreal. He gives news of his family's visit to Europe, and hopes that he will be able to join them in the spring and visit England.

• Fossils
• Geological Surveys
• Geology, Stratigraphic Cambrian
• Geology, Stratigraphic Devonian
• Geology, Stratigraphic Silurian
• Rocks, Metamorphic
• Rocks, Sedimentary
• Professional Interaction
• Social Interaction
• Unconformities (Geology)

• Dutton | Capt | Clarence Edward | 1841-1912 | American geologist, United States Geological Survey
• Geikie | Sir | Archibald | 1835-1924 | professor of geology, University of Edinburgh
• Gilbert | Grove Karl | 1843-1918 | American geologist
• Selwyn | Alfred Richard Cecil | 1824 - 1902 | geologist and director of the geological survey of Canada

• United States Geological Survey (USGS)

• Cascade Range (United States)
• Grand Canyon (Arizona, United States)
• Hawaii (United States)
• Huron, Lake (Mich. and Ont.)
• Montreal (Quebec, Canada)
• Superior, Lake