This detachment accordingly left New York on the 22d May.  On reaching Quebec it was found that the proper persons could only be engaged at Trois Rivieres.  A delay was thus occasioned before this part of the duty could be performed.  The detachment, however, reached Rimouski 4th June, where the snow was still found upon the ground and the river barely fit for the access of boats.  No time had therefore been lost, and the reconnoissance of the river was successfully performed.  The detachment, after passing all the establishments of lumberers, extended its explorations beyond the remotest Indian paths, and leaving its boats penetrated on foot several miles to the south of the highest point of the stream in which boats could float.  In this progress through unexplored ground a lake wholly unknown was discovered.  The results of this expedition were embodied in a map, which on examination by parties furnished with better means was found accurate.

It was found by this party that the Rimouski presented difficulties which would forbid its ascent by a party provided with stores and instruments for the prosecution of a survey along the height of land, and that it would be impracticable even to make it the route of an expedition to reach its own source.  The little knowledge which was possessed of its upper course and the fact that it had probably never been explored even by Indian hunters were accounted for by its difficulty of access, which would forbid the carriage of a sufficient supply of provisions for consumption during its ascent and descent.  On other streams difficulties of this sort had been and were afterwards overcome by the use of the bateaux of the Penobscot, of greater burthen and strength than the birch canoes, but the continual repetition of portages on the Rimouski forbade the use of any vessel heavier than the latter.

2.  The main body of engineers, etc., was ordered to assemble in New York on the 15th May, for which time a vessel was chartered for the purpose of conveying them, with stores sufficient for an expedition of five months and the necessary instruments and camp equipage, to Metis, on the St. Lawrence.  The experience of the former season had shown that the country was so poor as to furnish little for the support of a numerous party, and it was believed that even game and fish would be found scarce at the points where supplies would be most needed.  It was therefore to be chosen between laying in the supplies in New York or in Quebec, and while the great advantage of conveying all the important instruments by sea turned the scale in favor of the former place, it has been ascertained that the decision was in other respects correct, for the dangers and difficulties of navigating the St. Lawrence might have frustrated altogether, and would certainly have materially delayed, the commencement of the main survey.

The sailing of the vessel was delayed, in expectation of the arrival of instruments from Europe, until the 30th of May, when a sufficient supply for beginning the operations arrived.