788 R OLLIN D. S A LI SB UR V 



The transverse veins appeared to belong to more than one 

 category. In some cases they seemed very much like the longi- 

 tudinal veins, while in other cases they seemed to be compar- 

 able to dikes. In places, these dike-like veins were as much as 

 three or four feet thick. Locally they were of compact blue ice 

 near their front and back walls, while the central portion was 

 notably more granular. On the melting surface this resulted in 

 a little ridge on either margin of the vein, with a slight depres- 

 sion in the center. Where a superglacial stream cut an ice gorge 

 across one of these dike-like veins, it was often seen that the 

 vein (or at least its walls) was of ice which was distinctly harder 

 (and bluer) than that on either hand. As a result of its superior 

 hardness, a rapids or waterfall was developed just below the vein, 

 and there was a tendency to ponding above, just as in the case of 

 a young stream cutting across a hard, vertical layer of rock. 

 The transverse-vertical veins were nowhere seen to be contorted, 

 or to present notably wavy outcrops at the surface. 



Contortion of the layers and laniince. — Professor Chamberlin 

 has already called attention to the contortion of the laminae in 

 the Greenland ice. In the glaciers which I saw, contortion of 

 laminae seems to have been less general than in the glaciers seen 

 by him. Indeed, most of the glaciers seen showed no consider- 

 able amount of contortion of lamina, though in some cases the 

 phenomenon was conspicuous. Its presence or absence seemed 

 to be dependent upon certain relations, some of which at least 

 were easily made out. 



The horizontal laminae are likely to be contorted about the 

 considerable lenses or masses of debris which are occasionally 

 incorporated in the body of the ice. This is shown in Fig. 15, 

 which represents a frequently repeated relationship. Great 

 masses or lenses of debris were rarely seen in the vertical face 

 of a glacier, without contortion of lamina, both behind and 

 before, though the laminae of ice above and below were not usu- 

 ally affected by contortion. 



A second position in which the contortion of horizontal layers 

 is common, is at the very base of the upper, clean part of the 



