8 
Bulletin of Natural History Society. 
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. Hr. 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. Hr. (Sir 
Wm.) Hawson 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, Mi\ Hartt was appointed one of its 
