Chautauqua Grape Belt. 



145 



The gravel ridges. — In passing from one end of the district to 

 the other, numerous differences are found in the g-ravel rids-es. 

 Perhaps the most important change is in the number of beaches 

 (Fig. 67). From the base of the lowest to the crest of the highest, 

 there is a vertical range of from 85 to 100 feet* in a distance which 

 is often less than a half mile. In this distance there are always 

 two distinct ridges or beach terraces and usually several. There 

 seem to be five beaches, though it is rare to find all developed in 

 the same section. In thirty-one sections whose elevations were 

 measured with the aneroid barometer, only one (Number 17) clearly 

 exhibited five ridges. In section 1 there are six gravel ridges, but 

 one or two of these may have been bars opposite the stream mouth. 



2 3 4 5 6 7 6 9 '0 II 12 13 I* 15 16 17 18 f9 20 2r Q2 23 24 25 2e' 2'7 28 29 30 ,3J 



SI. 



S2. 



247.1 



S.3 



i 



I 



n 



-67. — Diagram to show the elevation of the different terraces (in thirty-one sections) above the 

 base of the lowest terrace. 1, at State Line ; 30, just east of Silver Creek. 



There are four beaches in section 10, in which the upper beach was 

 not measured ; and there are also four in Section 31 where the 

 upper beach is absent. In several places (nine sections, 8, 11, 12, 

 13, 22, 25, 28, 29 and 30) four beaches appear in the same north 

 and south line. On the other hand there are places where the three 

 lower beaches are merged into one terrace, or in which one or two 

 of the beaches are so indistinct as to be scarcely noticeable (notably 

 section 16). 



From State Line to Sheridan the upper beach is cpiite distinct ; but 

 east of that place this beach begins to lose distinctness and it disappears 

 just east of Silver Creek. The lower beaches extend eastward, one 



* The ol(>Tation of tLe lake is 573 feet above sea level ; and of the base 

 above the lake, as determined by a line of levels run at Portland, 147 feet. 

 Therefore at this point the base of the lowest beach ridge is 720 feet 

 above sea level. 



10 



