232 BULLETIN 109, UNITED STATES NATIONAL MUSEUM, 



stayed with me over two or three weeks before they left, finding the 

 occupation not so pleasant to them as they expected; and for my 

 part, seeing not much benefit from their help in consideration of tha 

 considerable increase of the expenses, I concluded to go on with the 

 work alone, simply assisted by ordinary laborers as packers, boat- 

 men, and cooks." 



The following summary of the methods pursued and results ob- 

 tained is taken from Doctor Rominger's manuscript notes : 



As a continuation of the survey in the Lower Peninsula did not, 

 under the then existing circumstances, seem to promise very im- 

 portant additional results, active operations were discontinued in 

 the area, and his efforts confined chiefly to examining the azoic 

 areas of the Upper Peninsula, a work which had been left in- 

 complete by Brooks and Pumpelly. He here soon became convinced 

 that this greatly disturbed and complicated complex of rocks could 

 not be satisfactorily studied without first making a detailed study 

 of a small area which should serve as a type and guide for subse- 

 quent work in the larger ones. He therefore selected an area near 

 Marquette, v.here nearly all the members of the azoic series were 

 displayed for the detailed study. As no good topographic map of 

 the region existed he undertook to construct one for himself, using 

 the Government Land Office maps as a base. In determining the 

 position of hills, watercourses, and the larger rock exposures, h© 

 measured the distances by pacing, and the directions by the ordinary 

 hand compass, taking section corners and quarter posts as initial 

 points for the measurements, and at the same time making his geo- 

 logical obervations. In this way he surveyed over 200 square miles 

 from the shores of Marquette westward. Commenting on this work 

 later, Rominger remarked : 



I candidly confess that had I to do this over again I would no more attempt 

 perform all the work myself, but would employ someone else to do the counting 

 of steps and observing the compass while I was engaged with the examination 

 of the geological features. Both occupations combined are too severe a strain 

 on body and mind. On the other hand, I am satisfied that this modua operamli 

 brought many things under my observation which otherwise would have es- 

 caped it. 



The map prepared in this way, it should be stated, is the one issued 



in connection with the fourth volume (1880) of the survey reports. 

 During the seasons of 1880-1882 Rominger continued his examina- 

 tion of the azoic rocks near Lake Gogebic in the western part of the 

 State, though a portion of the time was spent in a reexamination of 

 the Fetch Mountain, Menominee, and Marquette districts. During 

 the summers of 1883 and 1884 he devoted himself exclusively to the 

 examination of the copper-bearing rocks on Keweenaw Point and in 



