REVIEWS AND BOOK NOTICES. 
Tue Gro.ocy or THE Lower Amazonas.*—The Ereré-Monte- 
Alegre District and the Tuble-topped Hills. In this paper Prof. 
Hartt has given us a very interesting account of a part of his 
careful explorations on the Lower Amazonas. In the fall of 
1870, a month was spent in the vicinity of Ereré with three assist- 
ants, and in the following year, nearly as much time was given to 
the same neighborhood in company with Mr. O. A. Derby, his 
present assistant. A large portion of the ground was gone over 
on foot and field notes and sketches carefully made. The results 
of Prof. Hartt’s labors are of extreme interest, as they clear up 
many uncertainties in regard to the age of the sandstones and 
shales of Ereré, supposed by the late Prof. Agassiz to be of gla- 
cial origin. They really belong as far back as the Palæozoic age. 
_ Space will permit us to give but a brief outline of the main por- 
tion of the paper, in connection with the sketches illustrating it, 
the cuts of which have been kindly loaned by the Buffalo Society 
of Natural Science. 
To the northwest of Monte-Alegre, a town situated on the Rio 
Curupatiiba, near where it enters the Amazonas, and distant 350- 
360 miles nearly directly west of Pará, is quite an extensive 
Plain, surrounded on all sides by hills and high grounds. The 
distance across the plain from north to south is about fifteen miles, 
its width from east to west is over ten miles. It lies somewhat 
higher than the alluvial plains of the Amazonas, and is drained 
by the Igarapé of Ereré, a small stream flowing into the Igarapé of 
Paitúna, which in turn enters the Rio Curupatiba some distance 
below Monte-Alegre. The structure of the plain of Ereré is very 
simple, for it is composed of nearly horizontal strata of Devonian 
age, through which the small Igarapé has worn a little valley, 
harrow toward the north where the stream flows over the bare 
rocks, but broader below and partly filled in with alluvial depos- 
its, lying below the level of the plain. The rocks project in iow 
i bluffs along the edge of the valley, and about fifteen feet in thick- 
"ess of the Devonian beds are exposed, where the road from the 
BOW tres rae, Professor ae Geoogy im Coral Univers Balai of the 
Bufalo Society of Natural Science, vol. 1, No. iv, Jan., 1874, pp. 201-235 
_ AMER. NATURALIST, VOL. VIIL 43 
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