Chautauqua Grape Belt. 



147 



Variations in the gravel ridges. — Not only do the number of 

 the gravel ridges vary, but there is a considerable difference in 

 their characteristics from one point to another. Generally the 

 slope of the terrace front is abrupt (Fig. 68), and the top quite 

 level ; but, as has already been noted, it may be in the form of a 

 ridge or bar instead of a beach. There is also a variation in width, 

 which in some cases is very marked, Notably opposite the 

 mouths of streams the width of the gravel is greatly increased, 

 the deposit there being in the nature of a delta. Here the steep 

 front of the terrace disappears and is replaced by a gravel slope, 

 crossed by numerous gullies and traversed by ridges of gravel ; 

 and this gravel extends for a considerable distance toward the 



fT-r- 



k 









V%. 



=• — .>-, 



- ^ — ^ i^-C 



68.— Front face of lower beach terrace just west of Portland. East of section line No. 2, 



Fig. 67. 



lake, gradually becoming a sand, and then, near the lake, a clay. 

 The best delta in the area studied is that upon which the town of 

 Fredonia is situated ; but there are other similar deposits near the 

 mouth of nearly every stream of considerable size. 



Just as in the modern beach, there is also a variation in texture 

 in any single gravel ridge. But quite unlike the modern beach, 

 the material is always a gravel. In the entire region studied 1 

 have found no considerable part of either terrace made of sand. 

 In small areas there is often much sand ; but nearly everywhere 

 there are layers of rounded pebbles in close association. 



On the present shore there are many wave-cut cliffs of shale ; 

 but in the entire region occupied by the gravel ridges, from State 



