564 PROCEEDINGS OF THE ACADEMY OF [DeC, 



From the Avestern boundary of the Skaneateles quadrangle ta 

 Cayuga Lake continuous sections are rare, but there is always some 

 reference plane by which to check the position of the Mottville 

 beds. In the same area there are also some slight variations in 

 lithologic character, but these are clearly of a progressive nature, 

 becoming more pronounced by slow degrees from east ,to west. 

 Paleontologic characters are well maintained throughout the region 

 in question and one more evidence of continuity is afforded by the 

 escarpment which is frequently produced by the harder layers. 



The more important sections met with in passing from the Tully 

 quadrangle to Cayuga Lake are shown slightly idealized in Plate 

 XXIL 



Section 2 is exposed in a ravine situated west of Cottle Hill and 

 about f mile from the western limit of the Skaneateles quadrangle. 

 The harder portions of the Mottville are well displayed at this 

 locality and their position relative to the black Marcellus is beyond 

 all question, for the section is continuous. About 1| miles south- 

 westerly at nearly the same altitude and on the Auburn quadrangle 

 is found another exposure of the Mottville crinoidal layer and asso- 

 ciated shales. Here unfortunately the black Marcellus is not 

 shown below in continuous section. It is exposed, however, at a 

 lower altitude in a near-by ravine within j mile to the west. The 

 relation is the same as that shown in section 2. This easternmost 

 Mottville exposure on the Auburn quadrangle is an important one. 

 It can be connected loy a nearly continuous escarpment with the 

 Mottville layers of section 2. It agrees in its lithologic and paleon- 

 tologic characters with other exposures of the Mottville. It lacks 

 only a continuous section to prove its stratigraphic position above 

 the Marcellus. These points are emphasized, for this Mottville 

 exposure has apparently received a far different interpretation on 

 the geologic map of the Auburn quadrangle.^'' 



A little south of Half Acre and about If miles southwesterly from- 

 the Auburn city line a good exposure of the Mottville member is 

 obtained. Here its position above the black Marcellus can be 

 determined in a nearly continuous section while the relations with 

 the Agoniatites limestone and the Styliolina layers below it are 

 scarcely less clear. 



Passing toward the southwest in the direction of Oakwood the 



1" N. Y. State Museum Bulletin 137. See map and also p. 18, where one 

 finds the following statement: "The Agoniatite limestone and adjacent black 

 shales outcrop i mile from the east line of the ciuadrangle by the side of the 

 third east and west road from the north line of the quadrangle." 



