WOODWORTH: GEOLOGICAL EXPEDITION TO BRAZIL AND CHILE. 113 
Parana it forms crusts in the surficial decomposed portion of the bed 
rock. In a railway cut on the banks of the Iguassii near Serrinha 
Station in Parand the outer portion of the Carboniferous rocks is 
crusted with canga and this vein-like material there occurred in 
joints. The segregation of canga by percolating water seems mainly 
to be ancient; it may be older Pleistocene or still older, and probably 
is not peculiar to any one episode of the modern geological history of 
the region. 
The canga in some localities appears to have been broken up and 
transported, now occurring as rubble in the red surface deposits as 
between Sao Pedro de Itararé and Fabio Rego. In this case the canga 
must have been segregated prior to the transported red earth, and 
if the red deposit be assigned a Pleistocene date the canga may be 
referred to the Tertiary. 
The decomposed state of the rocks in Brazil was early recognized 
and correctly described by José Bonifacio de Andrada e Silva and 
_Martim Francisco Reibeiro de Andrada in an account of a mineralogi- 
cal journey from Santos to the tableland made in 1820. This article 
is reprinted in Ferreira’s Diccinario geografico das Minas do Brazil. 
Rio de Janeiro, 1885, p. 341, 342. | 
W ceather-blocks — The weathering of the granites along the coastal 
slope of the Serra do Mar has led to the production of thousands of 
rounded weather-blocks which are particularly evident at the present 
sea-level and just above within the zone of wave action, tuose above 
the present sea-level having had the fine material between them 
removed in part at a time when the land stood a few feet lower than 
it now does. Abundant examples are to be seen about the shores of 
Rio Harbor. The illustration, Plate 2, is from a photograph of a 
group of blocks-on the shore of Sao Francisco Harbor in Santa Catha- 
rina. In Madureira, a suburb of Rio de Janeiro, near Cascadura 
Station there is fine large block said to be movable (pedra movedi¢a) 
poised high up on a weathered tower of granite. The famous Furnas 
de Agassiz at Tijuco in the Serra near Rio de Janeiro is another group 
of weather-blocks, the most imposing to be seen anywhere in south 
Brazil. 
It remains to note certain rock benches and the uplifted fringing 
coastal plain to be seen along the shores from Rio de Janeiro to near 
Laguna on the south. 
From observations made about Sao Francisco Bay in latitude 26° S. 
I suspect that there exists along this coast an old bench of marine 
erosion 150 or more feet above the present sea-level. Numerous rock 
