PERMO-CARBONIFEROUS GLACIAL DEPOSITS Sh i847) 
observed. The whole series of rocks, including the two tills, 
seems to lie nearly horizontal, doubtless with a gentle dip north- 
westward following the regular trend of the stratification in south- 
ern Brazil. The tillite at Serinha looks no older than that described 
before, and may represent merely a Carboniferous forerunner of the 
more important glaciation to follow. 
Southeast of Ponta Grossa the railway lies too far west to give 
opportunities of observing the glacial deposits, passing over trap- 
sheets, Triassic sandstones, etc.; but I. C. White’s account of 
the bowlder conglomerates associated with a low grade of coal and 
Permian plants in the state of Santa Catharina, e.g., at Orleans, 
shows that tillite continues to latitude 28°.1 His map of the 
Tubarao series, which includes the Orleans glacial conglomerate, 
extends the tillite to the southern end of Brazil, in Rio Grande do 
Sul, though his account does not specially mention bowlder con- 
glomerates as having been observed in that part of the country. 
Guillemain, by finding tillite with striated stones at Fraile 
Muerto in northern Uruguay, not far from the boundary of Brazil, 
as noted in the introduction, continues the region of glaciation still 
farther to the south. Including the 500 kilometers reported from 
Sao Paulo this gives a length of about 1,500 kilometers from north- 
east to southwest, running in latitude from 223° to about 323°. 
The tillite has not yet been found to outcrop continuously for this 
long distance, but the known localities are sufficiently numerous 
to make its continuity highly probable. Its known width is 
estimated at from 50 to too kilometers in Sao Paulo, but it is 
unknown how far it extends beneath the Triassic sediments and 
trap-sheets to the northwest. 
TILLITE IN SIERRA DE LA VENTANA 
There is a long gap between the Permo-Carboniferous deposits 
of Brazil and northern Uruguay and the nearest outcrops of tillite 
discovered in Argentina, which are in the Sierra de la Ventana not 
far from Bahia Blanca. Dr. J. Keidel, chief of the Geological 
Section of the Argentine Survey, was good enough to plan an 
excursion to this locality for me. A rail journey of 537 kilometers 
tT. C. White, Relatorio Final on the Brazilian Coal Fields, 1908, pp. 11-13 and 51. 
