404 PETROLOGICAL ABSTRACTS AND REVIEWS 



from calcium carbonate and quartz at lower temperatures (mean about 900° C.) 

 to wollastonite and carbon dioxide. This and similar rules are exemplified by 

 the crystalline schists of the Christiania region. 



I 



GoLDSCHMiDT, V. M. Das Devongebiet am Rdragen hei Rores. 

 With a paleontological supplement: Nathhorst, A. G. Die 

 Pflanzenreste der Rdragen- Ablagerung. Christiania, 19 13. Pp. 

 27, pis. 5, maps 2, figs. 3. 



This is a report on the areal and structural geology of an area measuring 

 about 10 by 7 kilometers in south-central Norway, bounded on the north by the 

 Lake of Betnen, on the south by the Lake of Feragen. The sedimentaries 

 shown here are Cambrian, Ordovician, and Devonian, the last composing by far 

 the greater part. Granite, augen-gneiss, saussuritized gabbro, and basic peri- 

 dotite-serpentines are the igneous rocks. Chromite has been mined in the 

 last-named rock. The Devonian beds overlie unconformably the eruptives 

 and older sedimentaries; they consist of conglomerates, sandstones, and slates. 

 An especially interesting member of the Devonian sequence is a 200-meter- 

 thick serpentine conglomerate, of which the angular bowlders resemble breccia- 

 fragments of serpentine; at its base it goes over locally into white magnesite. 

 The total thickness of the Devonian is about 400-500 meters. 



Faulting has affected the pre-Caledonian sediments, and this was followed 

 by a period of intrusion from which date the eruptive rocks mentioned above. 

 The pre-Devonian beds dip toward the northwest. 



Devonian beds, however, have a general southeasterly dip. These sedi- 

 ments were probably deposited in a basin or basins of limited extent, formed 

 and filled during the middle Devonian. 



Illustrative plates and a brief description of the Devonian floras of the 

 region accompany the report. 



GoLDSCHMiDT, V. M. ''tjber einen Fall von Natronzufuhr bei Kon- 



taktmetamorphose," Neues Jahrh., XXXIX (1914), 193-224, 



pi. I. 



A study of contact metamorphism in sandstones of Norway. The unmeta- 



morphosed sandstones are somewhat arkosic (microperthite, albite, orthoclase, 



and microcline are the feldspars) and flakes of muscovite and chlorite are also 



present; the matrix is calcareous or argillaceous. These sandstones are 



Devonian or Silurian in age. When metamorphosed they normally become 



biotite-rich quartzite or even hornfels. WoUastonite is commonly developed. 



In other instances secondary potash feldspars, sometimes intercrystallized 



with plagioclase, appear in the matrix. Besides quartz, a pyroxene (heden- 



bergite) is very common. This description characterizes the normal type of 



metamorphism. 



