[146] It is to be regretted that Capt. Douglass, who, immediately on the conclusion of this expedition, was appointed to an important and arduous professorship in the U. S. Military Academy of West Point, could not command the leisure to complete and publish his map and topographical memoir of this part of the U. S. So long as there was a hope of this, my report of its geology, &c., and other data intended for the joint PUBLIC WORK, were withheld. But in revising this narrative, at this time, they are submitted in the Appendix. Prof. Douglass, of whose useful and meritorious life, I regret that I have no account to offer, died as one of the Faculty of Geneva College, October 21, 1849. Mr. Trowbridge, whom I had requested to note the features of its geology and mineralogy, presented me with labelled specimens of the succession of strata which he had collected on the route. These denoted the continuance of the calcareous, horizontal series of formations of the Fox Valley, and of the islands of Green Bay, quite around those northern waters to the closing up of the surveys at Point St. Ignace and Michilimackinac. Nor do the primitive rocks disclose themselves on any part of that line of coast. Of this collection, Mr. Trowbridge well observes, in his report to me, the most interesting will probably be the organic remains. These were procured on the northeast side of Little Nocquet Bay, where areas of limestone appear. They consist of duplicates of the pectinite. Three layers of this, the magnesian limestone, show themselves at this place, of which the intermediate bed is of a dull blue color and compact structure, and is composed in a great measure of the remains of this species. It is comparatively soft when first taken up, but hardens by exposure. About ten miles north of this point, the upper calcareous, or surface rock, embraces nodules of hornstone. Specimens of a semi-crystalline limestone, labelled "marble," were also brought from a cliff, composed of this rock, on the lake shore, about thirty to forty miles southwest from Michilimackinac. Mr. Doty also brought some specimens of sulphate of lime, cal. spar, and some of the common rolled members of the quartz-drift stratum.