. Bulletin of the Geological Society of America. Geology. 444 A. W. GRABAU PALEOZOIC DELTA DEPOSITS OF NORTH AMERICA 6 and 7). A disconformable contact with the underlying formations is further indicated by the Clinton of Ohio, which contains well-rounded foreign pebbles in its basal portion. The fact that the Juniata and suc- ceeding Siluric deposits of central Pennsylvania are essentially concor- dant in dipy though separated by a disconformity and hiatus, shows that the effect of the post-Ordivicic folding was not felt as far west as this. Figure 6.—Section of the Oolitic Iron Ores of the L
. Bulletin of the Geological Society of America. Geology. 444 A. W. GRABAU PALEOZOIC DELTA DEPOSITS OF NORTH AMERICA 6 and 7). A disconformable contact with the underlying formations is further indicated by the Clinton of Ohio, which contains well-rounded foreign pebbles in its basal portion. The fact that the Juniata and suc- ceeding Siluric deposits of central Pennsylvania are essentially concor- dant in dipy though separated by a disconformity and hiatus, shows that the effect of the post-Ordivicic folding was not felt as far west as this. Figure 6.—Section of the Oolitic Iron Ores of the Lower Siluric (2) resting discon- formaoly on Haquoketa Shales. Iron Ridge, Wisconsin region. The absence of Juniata and Bald Eagle beds in eastern Penn- sylvania, where they must have existed, since the material of which they are composed could only have been derived from the old land still farther to the east, is explained by the fact that the Taconic folding carried the bottoms of the synclines above the present erosion plane. When it is remembered that these folds were truncated, and that the region was essentially peneplaned in early Mesozoic time, and that, finally, Tertiary. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Geological Society of America. [New York : The Society]
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectgeology, bookyear1890
