4 Envin Hinckley Barbour 



The accompanying diagrammatic sketch of the fossil cork- 

 screw beds, as seen at Pine Ridge, just north of Harrison, will 

 give a fair idea of a section, although no accurate measure- 

 ments were made, except at Eagle Crag. (See Figure 1.) 

 The tops of all the surrounding hills are sand-rock underlaid 

 by alayer of light yellow flint, a foot or two in thickness, which 

 is quarried by the citizens of Harrison for foundation stones. 

 Directly below this layer of flint comes a very homogeneous 

 and fairly coherent stratum of sand-rock some eight hundred 

 to one thousand feet in thickness. The upper hundred, or 

 more, feet of this layer constitutes the Diamonelix beds. It 

 must not be inferred from this that there is any break whatever 

 between the Diamonelix beds and the rest of the layer. On the 

 contrary there is none. The marked uniformity of the whole 

 layer suggests continuity of sedimentation and freedom from 

 those seasonal variations which effect sediments. Below comes 

 marl, the continuation of which to the north becomes the 

 Bad Lands of the Hat Creek Basin. The whole deposit seems 

 undoubtedly and unquestionably aqueous in its origin. How, 

 then, could an animal have burrowed ? Possibly he burrowed 

 around the edges of a retreating inland sea. The author's 

 observation would lead him to say no. However, the strata 

 here dip to the south and east, and the suggestion above will 

 be followed out by the study of these beds during the summer 

 of 1894. 



The reasons for assuming that these fossils were contempora- 

 neous with the sediment around them are embodied in the ac- 

 companying description. 



Plate 1 shows Eagle Crag from the west. Three sides of 

 the Crag rise by nearly vertical walls. In the field, if not in 

 the cut, giant corkscrews can be seen on every hand through a 

 vertical range of at least one hundred feet. The slanting sum- 

 rait of Eagle Crag shows the tops of many corkscrews weath- 

 ered out on every level. Our best specimens were obtained 

 here, in some cases from walls entirely vertical. 



