414 NEW YORK STATE MUSEUM 



Jordan and Memphis these shales forming the walls and bottom 

 of the broad valley are eroded into forms simulating morainal 

 topography. (This resemblance of the shale erosion forms to 

 moraines is very pronounced all the way east to Oneida, and even 

 the experienced geologist who is new to the region will make wrong 

 diagnosis if he decides by the forms as seen from a distance.) 



In the Jordan-Memphis district the Vernon shales reach up 

 over 500 feet, while the lake and stream fillings in the valleys are 

 about 400 feet altitude. The Vernon shales, therefore, extend 

 upward about 100 feet above the lowlands and are overlain by the 

 somewhat harder but yet soft gypsum-bearing Camillus shales. 

 East of Jordan they form the common platform from which the 

 drumlins rise [pi. 9, 10]. But west of Jordan, as far at least as 

 Newark, the drumlins are situated much lower, their bases being 

 contoured [pi. 11,12] by the 400 or 420 foot contour, and many rising 

 out of the Montezuma marshes as if partly buried under lake 

 deposits. It appears, therefore, that in the Weedsport-Lyons belt 

 the Amnion and Camillus shales belong in the same horizontal plane 

 or topographic horizon as the drumlins, and the interesting and 

 important question arises if the drumlin forms may not be partly 

 shale instead of till. Some study of this problem has been made 

 with definite results. The drumlins- show only till at the surface, in 

 nearly all cases. Often this may be only a veneer or varnish of 

 drift rubbed into the soft shale. The West Shore Railroad has 

 several good cuttings through drumlins in the stretch west of Port 

 Byron which ought to reveal interior composition and structure, but 

 the cut slopes are so coated with wash from the upper material that 

 to casual inspection they appear as till. 



One and one half miles northeast of Port Byron the red Vernon 

 shales appear clearly on the slopes and at the summit of a drumlin- 

 shaped hill having a summit contour of 460 feet. This hill is 

 indicated in the lower left hand corner of plate n. Here we cer- 

 tainlv have a drumlin form in rock, a rocdrumlin. It is very likely 

 that other of the lower drumlin forms may be chiefly shale with 

 only a veneer of drift, and it is more than likely that some of the 

 larger drumlins have a base or core of shale. 



All the western central New York rocks have a decided southerly 

 dip It is evident, therefore, that north of the Syracuse-Lyons 

 parallel the strata should lie at increasingly higher elevation. 



