Geology. 825 
that, on the Amazonas, there is a fossiliferous series consist- 
ing of Carboniferous, Devonian and per Silurian, resting, un- 
conformably, not on the gneiss, but on an extensive series of quartz- 
ites superior to it. 
n southern Brazil, “os least, eat are "exttemely. rare in the 
gneiss series. The o ed definite ely known is a thin one in the 
Parahyba valley, well go ca at the Barra do Pirahy, where it 
was examined by Professor Hartt and myself. The river, both 
above and below oe flows along the strike of oo beds, whi ch 
is very regularly N. ., the limestone appearing at various 
points, at, or near ow river, abitil it makes a bend i the eastward 
and escapes from behind the Serra do Mar, above the city of Cam- 
pos. This distance is about 120 miles, About 30 miles above 
along the line of strike, limestone is fipoited near Barra 
nsa. 
It is remarkable that about 100 miles farther to the southwest- 
ward, limestone in the gneiss series is reported by Rath near 
Gnape, i in a locality which is almost exactly on the prolongation 
of the line of strike from Barra 
e bed at Barra is about fifty feet Spee enclosed in schistose, 
gametiferous pace and dips 60’ to the thward. 
The oarsely crystalline, te, Paihia , Showing a beau- 
tiful bluish tint 904 held to the light in thin pieces, and contains 
4 small amount of pale green serpentine, soft and greasy like tale, 
from aa ypc distributed in thin films along the planes of 
bedding. The serpentine is not distributed throngh the mass and 
nothing resembling Eozoon is to be found. Near the small village 
of Sta Anna de Pirapitinga, the farthest point to the northeast of 
Mara, where the limestone is known, I have lately had an oppor- 
tunity of examining it, through the kindness of my friend, Dr. J. 
A. de Sa Dis; who called my attention to it. The bed here has 
ar the 
oe no ome of the Sientity © of the be a. The surfaces expo osed 
writing the above, Me 1 , in ate course of 
explorations ths e Rio Sao Francisco, has Sacovered: a bed of 
Serpentine limestone, in the me phic series of the da 
: and Pirapitinga. A single small fragment of the 
Pirapitinga limestone, and several larger ones from po beds at 
araund, sent me by Mr. Derby, have been examin Dr. 
AM. Jour. Sct.—Turrp _— Vou. XLX, No. 112.—AprI1, Fv 
