144 CARNEGIE INSTITUTION OF WASHINGTON. 



Laue photographs of potassium iodide. Hazy diffraction effects, different 

 from the above, probably related to the famihar "asterism" phenomenon 

 and thus arising from a distortion in the crystalhne arrangement, have been 

 observed and briefly described. The data from the Laue photographs are in 

 complete accord with the previously assigned "sodium chloride arrangement" 

 of the atoms in crystals of potassium iodide. 



(504o) On the existence of an anomalous reflection of X-rays in Laue photographs. Ralph 

 W. G. Wyckoff. Science, 58, 52-53. 1923. 



This is an abbreviated account, without any data, of results of the experi- 

 ments described in the preceding paper. 



(505) Comagmatic regions and the Wegener hypothesis. Henry S. Washington. J. 



Wash. Acad. Sci., 13, 339-347. 1923. 



The paper is a brief attempt to apply a petrographic test to Wegener's 

 hypothesis that the two continents of North and South America were for- 

 merly united to those of Europe and Africa and that they split and began to 

 separate about late Cretaceous time, the two Americas sliding, upon a semi- 

 solid basaltic substratum, westward to their present positions. If this were 

 true, we should find many correspondences on both sides of the Atlantic 

 between areas of similar deep-seated igneous rocks (comagmatic regions), 

 so that these would correspond if the parts were fitted together again, in 

 their supposed original positions, just like the color areas in a jig-saw puzzle. 



The matter is discussed with considerable petrographic detail, into which 

 it is not necessary to go here. It is shown that the characteristic igneous 

 areas of the west coast of Norway have no corresponding areas on the east 

 coast of Greenland, and vice versa. The large area of basaltic lava flows 

 that formerly covered the whole of the North Atlantic between Greenland 

 and the Faroes and Franz Josef Land is held to be an entirely independent 

 incident in the earth's history, analogous to the vast areas of basalt flows in 

 the Oregon region, India, Siberia, South Africa, Patagonia, and elsewhere. 

 Similar correlations are made between the comagmatic regions of igneous 

 rocks of Great Britain and those of Labrador and New England, the rocks 

 of France and Portugal and those of the Appalachian region, the rocks of 

 the north coast of the Gulf of Guinea and those of the Guianas and northern 

 Brazil, and the rocks of the southern west coast of Africa and those of the 

 east coast of South America (eastern Brazil and Argentina). 



Although there are a few minor correspondences, the discrepancies are 

 far more numerous and are of major size and importance. The conclusion 

 is drawn that the evidence of comagmatic regions is adverse to Wegener's 

 hypothesis. Wegener's view that the volcanic islands of the Pacific Ocean 

 are fragments of a broken, largely granitic crust covered by later lava flows is 

 disproved by the total absence of inclusions of granitic, metamorphic, or 

 sedimentary rocks in their lavas. 



(506) The fusion of sedimentary rocks in drill-holes. N. L. Bowen and M. Aurousseau. 



Bull. Geol. Soc. Amer., 34, 431^48. 1923. 



When a core sample of the beds penetrated is taken during the drilling 

 of an oil well, it is found under some conditions that part of the core consists 

 of a slag-like mass bearing some resemblance to a natural lava. This slag 

 has been pronounced by some geologists to be the result of fusion of rock in the 

 drill-hole as a result of the heat of friction, though some operators have 

 been unwilling to accept this conclusion. The examination of two drill-cores 

 sent us by Professor Bailey Willis, in one of which the beds immediately above 

 the slag were well preserved, has confirmed the opinion that the slag is the 

 result of fusion of the sedimentary rock in place. Chemical analyses of it 



