“SUCH A SECTION AS NEVER WAS PUT TOGETHER BEFORE": LOGAN, DAWSON, LYELL, AND MID-NINETEENTH-CENTURY MEASUREMENTS OF THE JOGGINS SECTION
In July of 1843, William Edmond Logan (1798-1875) began his first field project as the head of the newly established Geological Survey of Canada: the search for coal on the Gaspé Peninsula of Lower Canada. Logans activities in present day Quebec are well documented, but there is little record of his journey through the Maritime coalfields in the preceding month.
Two previously overlooked field notebooks contain information about Logans most important undertaking in Nova Scotia: measurement of the famous Joggins section. Inspired by Abraham Gesner and Charles Lyells reports of 40-foot-tall fossil lycopsid trees, Logan spent 5 days in early June measuring 14,570 ft. 11 in. of section exposed along the shore of the Bay of Fundy. Widely regarded as a meticulous, bed-by-bed section, Logans notes reveal that only coal-bearing intervals were measured directly; values for the rest of the section were based on paced distances, many of which were not converted to thickness until after he left Joggins. Realizing that his section was too detailed for scientific journals of the day, Logan published it as an appendix to his Report of Progress for 1843 where it went little noticed for many years.
J.W. Dawson and Charles Lyell briefly visited Joggins in 1852 and measured their own 2,819 ft. 2 in. log of the coal-bearing interval. Their more detailed section was published in the Quarterly Journal of the Geological Society of London (1854) and the first edition of Acadian Geology (1855). Having discovered Logans section after completion of his own, Dawson included a précis of it in his publications and noted that the two contained only minor differences. Careful comparison shows that they differ in thickness by 3 to 8% and that observations for even the most distinctive beds differ radically. Dawson cleverly disguised these discrepancies in later editions of Acadian Geology by abandoning many of his own observations in favor of Logans.
These measured sections are the foundation upon which our understanding of the Joggins section is built, but until recently our understanding of their methods consisted only of a simplistic picture of heroic effort. Using field notebooks, letters, and published papers we provide the first detailed information about how these Victorian luminaries constructed their remarkable sections.