Transactions and Proceedings and Report of the Royal Society of South Australia, Vol. 7

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Excerpt from Transactions and Proceedings and Report of the Royal Society of South Australia, Vol. 7: For 1883-84Crossing the spur dividing Stony Creek and Limestone Creek, the porphyries are seen to be penetrated by strings and veins of quartz, and in some places to assume an almost vesicular appearance. At lower levels towards Limestone Creek, the sedimentary rocks again appear, consisting of finely laminated slates, sandstones, and interbedded bands of whitish marble or dense blue limestone, dipping W. At 700. The marble bands are from 10 to 250 feet thick, more saccharoidal than the Stony Creek deposits, but full of seams of limonite, parallel to the bedding planes, and much jointed, they are also perforated by numerous caves. On the grassy sub-alpine ¿ats of Limestone Creek are deposits of auriferous Tertiary gravels from 5 to 12 feet deep. Ascending the steep spurs to the west, the slates become more corrugated and micaceous. On the upland ¿ats, near the crest of the range, masses of diorite are seen, the rich carpeting of grasses proving the fertility of the soil decomposed from these potash-yielding rocks. These intrusive masses are probably connected with the periods of Palmozoic volcanic activity, as the rocks at con tact are indurated and otherwise altered. As the crest of the range is reached, the slates become very much corrugated, micaceous, and full of quartz veins, further to the north, along the line of these semi-altered slates, veins of micaceous iron-ore are plentiful in a quartz matrix. On the crests of the range the rocks assume a vertical dip and decidedly meta morphic character as gneissose schists, while in descending towards Marengo Creek masses of granite are seen standing out in huge tors. This is probably a metamorphic granite, and is continuous across the valley of the Marengo Creek to Mount Leinster, which is a bold rounded peak on the Dividing Range. At the summit of this mountain the granite gives place to quartz-porphyry of an intrusive character, which has ap parently been exposed by sub-aerial denudation.About the PublisherForgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.comThis book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully, any imperfections that remain are intentionally left to preserve the state of such historical works.