LOG OF THE SENIGON WELL, SOUTHERN QUEBEC
In 1942 a well was drilled to a depth of 2296 feet 40 miles south of Montreal. Black shale predominated down to 2090 feet, and the lowest 206 feet consisted of Trenton limestone. Examination of the graptolites and other fossils allows a correlation with the known Montreal section. The Trenton-Utica boundary occurs midway in the shales, and the limestone below is correlated with the St. Michel member of the Montreal formation. The stratigraphic units are uniformly thicker here than at Montreal, presumably because they were deposited within the limits of the Appalachian geosyncline. Because mere reference to graptolite species would not suffice, descriptions of many found in the core are given.