118 Canadian Record of Science. 



bitt Mills, where the well-known auriferous slates are im- 

 mediately overlaid, unconformably, by conglomerates, grits, 

 and sandstones of Lower Carboniferous age. The lower 

 portion of these rocks contains an abundance of gold, which 

 was undoubtedly extracted from the underlying slates, 

 while the former deposits were in process of formation, and 

 was mixed with the loose gravelly material, which subse- 

 quently became consolidated into the conglomerate and 

 sandstone. 



We owe to Hartt also, the careful investigation of the rela- 

 tions of the different members of the carboniferous limestone 

 deposits in the neighborhood of Windsor, Stewiacke, &c. in 

 Nova Scotia. He collected and studied the fauna of each 

 separate set of beds with much pains, and in this way was 

 enabled to determine their sequence. The fossils which are 

 marine, are very numerous, and some new species were des- 

 cribed by him in the " Acadian Geology." Much interest 

 attaches to the study of this formation at the above localities, 

 where, in the upper beds, occur many forms common to 

 both the Carboniferous and the Permian, and a great like- 

 ness is apparent to the upper members of the Carboniferous 

 system in the western United States, called Permo-Carboni- 

 ferous. Dr. Meek, who examined the fossils, suggested 

 that we might have here what Barrande would call an upper 

 Coal-Measure or even Permo-Carboniferous fauna, 'colon- 

 ized' far back in the Sub-carboniferous period. Dr. (Sir 

 Wm.) Dawson has enlarged on Hartt's results, and shows 

 that the divisions made by him are of more general appli- 

 cation than Hartt had known them to be. 



As early as this, Hartt developed a constitutional tendency 

 to asthma, which interfered with his field work in the 

 cold and humid climate of this region, and which, after he 

 entered on his professional work in the United States, pre- 

 vented him from revisiting his native land. This, probably, 

 was one of the causes which induced him to seek occupation 

 in the warmer climate of Brazil. 



Upon the organization of the Thayer Expedition to Brazil, 

 by Prof. L. Agassiz, Mr. Hartt was appointed one of its 



