218 



almost no fossils iu form to be identified, but only small fragmental and 

 finely comminuted shells very firmly compacted. This triturated and 

 very compact character of the rippled surface is not confined to the sur- 

 face, but extends to a slight depth, gradually shading into coarser shell 

 fragments. 



The first layer below the stratum bearing the ripples contains substan- 

 tially the same fossils, with possibly a still larger proportion of Leptacna 

 scricca, and an occasional specimen of each of the following, viz.: Zygospira 

 modesta, Orthis testndinaria, and Crania scabiosa. This layer indicates a 

 somewhat agitated condition of the water In which it was deposited. 



Above the layer of tough, pasty blue clay which covers the rippled sur- 

 face, lies a consolidated layer consisting of whole and fragmental fossils 

 cemented by hardened clay. The shells and fragments are, so far as ex- 

 amined, pitched at all angles and crowded together in a way to indicate 

 an agitated condition of the waters during their deposition. There appear 

 to be few, if any, species in this upper layer different from those already 

 named. 



We conclude that the undulations referred to in this paper are ripple 

 marks for the following reasons: 



1. The axes of the series in general are pai'allel, yet with some varia- 

 tion in direction and continuity such as is seen in ripple marks formed on 

 sandy bottoms now. 



2. Thfe crests of the entire series are spaced with approximate uni- 

 formity; that is, there is no increase or decrease in distance from crest 

 to crest in pjissing from one edge to the other of the exiwsed area, which 

 might be the ease if the imdulations were beach marks. 



3. The fragments composing the surface of this stratum are much 

 finer than those found in the bottom, and finer tlian most of the frag- 

 ments in the strata lying above and below. 



4. The arrangement of fragments in the strata lying next above and 

 next below give evidence of considerable agitation of the water at the 

 time those strata were being deposited. 



The accompanying plates show the appearance of the ripple marks. 

 Plate I. is from a photograph, up-stream view; Plate II., the down-stream 

 view; Plate III., a small iwrtion of bed of stream, looking downwards 

 from the high right bank of sti'eani. 



