24. 



portion of the creek, and when the water is high, it is 

 practical!}' impossible to pass along the foot of the cliff. 

 The greatest height of the section is sevent\'-seven feet, but 

 it becomes much lower towards its down-stream end. The 

 dip of the strata, as determined from the Styliolina lime- 

 stone, is about four degi-ees to the south-east, giving an 

 average rise of one foot in one hundred and fifty. The 

 section has a length of about six hundred feet. 



At the upjxM" end of the section, between twenty-five Jind 

 thirt}^ feet of the Black Naples ((lardeau) shales are exposed, 

 the line of demarkation between them and the underlying 

 Cashaqua shales being ver}-- distinct. (See Fig. a, PI. VII.). 

 The whole of the latter rhales are exposed, including seven 

 distinct courses of concretions. The line of sc})aration 

 between the Cashaqua and the Genesee shales is not so 

 strongly defined, the latter, however, exhibiting their 

 characteristic jointing and fissility. (Fig. b, PI. VII.). The 

 Styliolina limestone has a thickness often inches, its upper 

 portion having a shaly character. At the upper end of the 

 section it forms the basal laver, projecting as an extensive 

 shelf beyond the bank. Its surface here is very uneven, 

 showing the same semi-concretionary character exhibited 

 under the bridge at Section 1 , and wherever a large area of 

 its surface is exposed. At the lower end of the section the 

 Styliolina limestone is about four feet higher, and frequently 

 projects from the bank when the shale beneath has been 

 \vorn away. The disintegi'ation and falling of the shales 

 above furnish material for the accumulation of a talus on 

 this shelf, which may remain in this position long enough 

 for vegetation to o^row. Sooner or later, ho\vever, the 

 undermining is carried so far that the projecting limestone 

 blocks break off, and with their loads of debris, tumble into 

 the stream. The Conodont limestone is not represented in 

 this section. 



The whole four feet of the upper Moscow shales, which 

 contain the Spirifer tullius fauna, are exposed at the lower 



