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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1916 Excerpt: ... foreign bodies, such as algae, etc., which were floating in the water, and forms the small spheres, rarely larger than pinheads, which are the chief constituent of oolites. Aragonite formed in salt water thus appears to be an important primary constituent of rocks, yet sedimentary rocks consisting of aragonite are very rare to say the least, for upon the subsequent removal of the salt, the aragonite, which represents a labile state of the carbonate, was re-formed as calcite. At the same time the original texture of the rock (cf. Figs. 5 and 6, PL VI) gave place to one which was more crystalline. Fresh-water limestones, calcareous sinter, calcareous tufas, stalactites, etc., are calcareous chemical sediments precipitated from fresh water by means of alga, moss, and the like, which withdraw the carbon dioxide from the dissolved bicarbonates, thereby causing the simple carbonate, which is not very soluble, to separate. Such deposits from fresh vadose water are distinguished with difficulty from others that are due to juvenile springs, such as the so-called Sprudelschale of Carlsbad which is of considerable magnitude. While these deposits, especially when from hot springs, also contain aragonite in the incrustations, they have undergone no diagenetic processes which could have destroyed it. Some of these rocks from juvenile springs consist Fig. 64.--Pea-stone from Carlsbad. of crystalline aragonite-spherules as large as peas, and called pea-stone or pisolite (Fig. 64). Subordinate in amount, and probably derived exclusively from juvenile springs, is the siliceous chemical sediment, siliceous sinter. This is deposited especially by geysers, in many cases with the aid of certain siliceous organisms which live in hot waters. Here are to be included also many depo...

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