. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. woodworth: geological expedition to brazil and chile. 93 consequence of erosion. In the section which can be constructed from the exposures along the road from Rio Negro to Lages at the pass through Collectoria it is possible that a fault can be traced cutting off the Espigao from the main mass of trap on the south at the right of the section in Fig. 24. But this interpretation of the. Fig. 24.— Section the Serra do Espigao at tlie Collectoria on the road from Rio Xegro to Laeres. tilted beds at the bottom of
. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. woodworth: geological expedition to brazil and chile. 93 consequence of erosion. In the section which can be constructed from the exposures along the road from Rio Negro to Lages at the pass through Collectoria it is possible that a fault can be traced cutting off the Espigao from the main mass of trap on the south at the right of the section in Fig. 24. But this interpretation of the. Fig. 24.— Section the Serra do Espigao at tlie Collectoria on the road from Rio Xegro to Laeres. tilted beds at the bottom of the valley and the apparently lower level at which the trap lies south of the stream crossing demands a throw of the normal fault on the south side in a manner nowise supporting the hypothesis that the escarpment is due to a fault. This northerl}- steep dip has by some been regarded as cross-bedding and is stated to occur elsewhere along the trap escarpment in the underlying sandstones. Number of the trap sheets.— It is stated that there are four trap sheets or sets of sheets in the trap mass of the Serra Esperan^a on the tAGfi roftr ^os Fig. 25.— Cross-section of the Trap plateau from the Rio Negro to Lages. 1 (dotted). Sao Bento beds. Triassic. 2 (right lined). The Collectoria trap sheet. 3 (cross lined). The Corisco trap sheet. 4. The Third (and Fourth?) trap sheets. north of the valley of the Rio Iguassu. In Dr. Derby's section the trap is diagrammatically represented as if composed of surface flo\\s. The number of flows or sheets entering into the plateau between the Serra do Espigjio and the sandstone area about Lages was not de- finitely determined by observation upon the ground but the plotting of the profile of the route and the outcrops of sandstones encountered in the trappean tract leads to the conviction that along this route there are at least three great sheets of trap separated by sandstone beds. The sul)joined figure section (Fig. 25) gives the appro
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