The Quarterly journal of the Geological Society of London . crinoids, and other calcareous organisms, all traces oflime seem now to have disappeared. The only exceptions met withare in some of the rocks at Bamshorn Down and the Chudleighdistrict, in which a small quantity of lime is present. VI. Microscopic Characters of the Badiolarian Bocks. For the study of the rock-structure and the radiolaria we havehad about 300 thin sections prepared from the typical rocks in thedifferent localities mentioned above. These show under the micro-scope a general resemblance in consisting of a siliceous grou
The Quarterly journal of the Geological Society of London . crinoids, and other calcareous organisms, all traces oflime seem now to have disappeared. The only exceptions met withare in some of the rocks at Bamshorn Down and the Chudleighdistrict, in which a small quantity of lime is present. VI. Microscopic Characters of the Badiolarian Bocks. For the study of the rock-structure and the radiolaria we havehad about 300 thin sections prepared from the typical rocks in thedifferent localities mentioned above. These show under the micro-scope a general resemblance in consisting of a siliceous groundmass,in some cases clear and transparent, in others dark and turbid fromthe presence of fine particles of carbonaceous or ferrous materials 1 Palseontographica, vol. xxxviii. (1892) p. J. G. S. No. 204. 2 t Fig. 2.—Microscopic Section of Radiolarian Rock, showing casts ofJRacliolaria. From the Lower Culm Measures at RamshornDown, near Bovey Tracer/, Devon. From a photograph takenby Mr. J. J. H. Teall, (Enlarged about 35 diameters.). Fig. 3.—Microscopic Section of Radiolarian Rock, showing Radio-larian casts and a cube of pyrites {the dark spot). From theLower Culm Measures at Carzantic Quarry, near Launceston,Cornwall. From a photograph taken by Mr. J. J. H. Teall, (Enlarged about 32 diameters.)
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Keywords: ., bookcentury1800, bookdecade1840, bookidquarte, booksubjectgeology
