Geology and Mineralogy. 505 



in clear waters, while the limestones with conglomeratic materials 

 were laid down ' ' during- periods of glacial action. ' ' These forma- 

 tions comprise the Torrowangee series. The tillite series with 

 its striated boulders is thought to be of the same age as that of 

 South Australia, referred by Howchin to the Cambrian. 

 Andrews, however, after reviewing this matter, concludes that 

 the Torrowangee series is clearly Pre-eambrian in age, "and 

 may be compared with Coleman's Huronian tillites." The 

 next younger strata, which originally covered all, are Cretaceous 

 in age. It is to be hoped that the Australian geologists will 

 now determine the age of the tillites of South Australia, which 

 are known to underlie marine and fossiliferous Lower Cambrian, 

 because it may turn out that these southern tillites are not con- 

 temporaneous with those of the Broken Hill area, but that the 

 one series occurs near the base of the Proterozoic, the other 

 toward the close of the same era. If Andrews' surmises are 

 correct, and the tillites of the region about Broken Hill are of 

 the age of Coleman's Huronian tillites in Canada, then there 

 will be established the supposition that in early Huronian time 

 the world had a glacial climate. No finer historical problem 

 in all Australia awaits the discerning geologist, since the tillites 

 of glacial climates are, when properly dated, the most exact 

 criteria for the dating of intercontinental geologic events, o. s. 



6. On the Eclogites of Norivay; by Pentti Eskola. 

 Videnskapsselskapets Skrifter. I. Mat. — Naturv. Klasse. 

 1921. No 8, pp. 118, with 14 figures and 3 plates. Christiania, 

 1921. — The eclogites of Norway are found to be of igneous 

 origin, in agreement with the conclusions previously reached by 

 Norwegian investigators. At Nordf jord and More the eclogites 

 occur as lenses in protoclastic granite-gneiss, where they appear 

 to be of the nature of cognate xenoliths, and other masses are 

 enclosed in dunite. In the Bergen area eclogite occurs as 

 segregations in anorthosite. The author has investigated the 

 eclogites quantitatively in careful detail : by bulk chemical 

 analyses ; by determination of the mode, generally by mechanical 

 separation of the constituents by means of Clerici's solution; 

 and by chemical analyses of the component minerals and determi- 

 nation of their refractive indices and specific gravities. The 

 garnets of the eclogites prove to be calcium-bearing members 

 of the pyrope-almandite series, of rather wide range in compo- 

 sition. The purpose of this detailed investigation is to obtain 

 fundamental data for what the author calls facies petrology 

 (or heteromorphism, if that term is used in a somewhat more 

 generalized sense than Lacroix has given it). 



Adolph Knopf. 



Am. Jour. Sci.— Fifth Series, Vol. IV, No. 24. — December, 1992. 

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