GLACIAL WATERS IN THE LAKE ERIE BASIN 



17 



part of the Cattaraugus valley. Some 6 or 7 miles west of the 

 Machias outlet is a pass near West Valley with altitude over 1700 

 feet which could have been the point of overflow of only the local 

 waters of the Ashford creeks since it was higher than the Machias 

 outlet that was already open. 



The next effective channel, later in time and lower in altitude, 

 is at the Persia flag station between Dayton and Cattaraugus 

 stations of the Dunkirk branch of the Erie Railroad, some 7 or 8 

 miles southwest of Gowanda. The head or intake of this channel 

 is close to the steep west bank of the south branch of the Cattaraugus 

 creek. The water-parting is a swamp and the channel is about 

 J mile wide. The channel leads northwest % mile, where the rail- 

 road crosses it by a low filling, then curves around sharply to 

 the southwest and opens into a valley tributary to the cast branch 

 of the Conewango. As it is about 300 feet lower than the Machias 

 outlet it probably succeeded the latter as the outlet of Cattarau- 

 gus glacial waters. 



All the other outlet channels which carried waters from the Erian 

 basin over into southern or Allegany flow are represented in the 

 accompanying maps, except possible points of overflow west of Chau- 

 tauqua lake in a district not yet surveyed for the topographic map, 

 but which are doubtless inconsequential as the waters could have 

 formed only small lakes close to the divide. 



In the district between Mayville, at the head of Chautauqua 

 lake, and Westfield, near Lake Erie, there is an interesting com- 

 plexity of the drainage, shown in plate 2. The branches of Chau- 

 tauqua creek (which has no relation to the lake of that name but 

 drains the Erie slope, passing northwest through Westfield) have 

 cut three deep "gulfs" in the Portage shales and the features 

 which were left by the glacial drainage are somewhat obliterated. 

 The earliest and highest overflow of the glacial waters in this 

 district is shown on the map as 3 miles west of Mayville, with 

 altitude according to the map contours under 1380 feet, the waters 

 escaping east to Chautauqua lake. A later, lower and more important 

 southward outlet for the waters of the ancient Chautauqua creek 

 valleys is abroad swamp col at the head of the Little Inlet creek, 

 2h miles north of Mayville, with map altitude 1320 feet. These 

 cols must have been uncovered by the ice retreat so nearly at 

 the same time, judging by their relation to the general slope, that 

 the earlier and higher outlet could have been effective onlv a 

 relatively short time. 



