One of a recent batch of samples from the Serra da Baliza, in the state ofParana, Brazil, contained asphalt and a dark heavy oil; and workmen on therailway from Porto Uniao to Uruguay discovered asphalt coming from eruptivesthat outcrop along the Rio de Peixe. The occurrence of asphalt in the triassiceruptives of southern Brazil, however, has been known a long time, according toDr. Gonzaga de Campos. It is generally believed that the Botucatu sandstone is always a hard vitrifiedrock, from the metamorphic action of the overflowing eruptive contacts. In thisregion, however, the contact metamorphism is almost nil; the sandstone isslightly hardened in a narrow zone about 20 to 30 cm. wide. In many places, thesandstone is so friable as to be easily reduced to sand, which is used inmortar for building in Guarapuava and Palmas. South and west from Porto Uniao, this bench of sandstone is about 50 m. thick, and is capped by a heavy bed ofbasic eruptives, many of which are amygdaloids. Nature of Rocks Dr. Geo. P. Merrill, after studying the triassic eruptives collected by theCoal Commission, reached the conclusion that "All these rocks are oftypical basalt-diabases, not in any essential different other than instructure. An interesting mineralogical phase is its paucity in olivine, whichin many cases is completely lacking." Professor Russak, who carefully studied these rocks and their accessoryminerals, decided that in the dikes they are granular (diabase) and that in thelava sheets, porphyritic (augite-porphyrite or melaphyre), and that the latterpass evidently to normal diabases and are always typical of effusive rocks. Theexamination of many slides from dikes and sheets leads us to adopt the opinionof Professor Russak; the rocks of the dikes are of ophitic structure, whilethat of the sheets show a great variety of structure and may vary from almostgranular to basaltic. The great paucity in olivine had been noted by Russak, who classes as melaphyres, the porphyritic triassic rocks in Brazil whichcontain olivine. AIME 065–26