. [Reports]. ut nine feet from the top. Thesecond occurs 48 feet from the top. The upper feet, however,is essentially a dolomitic horizon; the middle 79 feet is essentiallya calcareous horizon; and the lower 39 feet is essentially a dolo-mitic horizon, although the conglomerate bed nine feet from thebase is a limestone. About 63 feet below the top of this formation there occurs4 feet 6 inches of soft blue shale, in which are embedded largeand small boulders of crystalline limestone known together asCentral marble boulder member. This marble occurs frequentlyin the form of well rounded bou
. [Reports]. ut nine feet from the top. Thesecond occurs 48 feet from the top. The upper feet, however,is essentially a dolomitic horizon; the middle 79 feet is essentiallya calcareous horizon; and the lower 39 feet is essentially a dolo-mitic horizon, although the conglomerate bed nine feet from thebase is a limestone. About 63 feet below the top of this formation there occurs4 feet 6 inches of soft blue shale, in which are embedded largeand small boulders of crystalline limestone known together asCentral marble boulder member. This marble occurs frequentlyin the form of well rounded boulders but usually in masses whichhave flat bases and smooth roundish upper surfaces. In someplaces, for example along Davis creek near the southwest line ofLand Grant No. 3272, these boulders look very much as thoughthey were a part of a continuous bed. Here they occur in roughlyrectangular blocks having smooth roundish upper surfaces, irregu-lar water-worn sides and flat bases. These boulders resist weather-. DAVIS FORMATION. 35 ing better than the shale in which they occur, on account of whichthey protrude at the surface. The weathered surface of theseboulders is white on account of which they stand out in strongcontrast to the dull yellowish or greenish shale background. There appear to be two somewhat distinct types of this marble,one being very finely crystalline and having a mottled bluish graycolor, the other being medium to coarsely crystalline and havinga grayish color. The color of the weathered surface of the formeris white while that of the latter is yellowish brown. Both are moreor less mottled with spots and streaks of green and chocolate fine grained marble contains a great many fossils and in oneplace the surface of one of these boulders was thickly strewn withfragmentary trilobite remains. These boulders are usually under-lain with a conglomerate about a foot in thickness, with which theboulders frequently coalesce and to which they are frequently at-
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