172 



NEW YORK STATE MUSEUM 



ceeds. The largest one, a most striking example of this kind, is the 

 inlier of Beekmantown rocks along West Canada creek, extending 



In! ier 



m esto ne 



Lo 



U 



Fig. io Diagrammatic section of Three Mile Creek inlier. 



dicates the creek. 



The black line in- 



abont 12 miles from above Poland to a few miles below Middleville 

 [see text fig. n]. Above the mlier the river flows on Trenton 

 limestone and below on alluvium, which, however, rests quite surely 

 on Trenton and younger rocks, as evidenced by Cushing's map of 

 the Little Falls quadrangle. If it should continue down the river, 

 it would be connected with the Little Falls inlier of Beekmantown 

 and Precambric rocks, which is principally due to block tilting. 



\\ Tiile the West Canada creek inlier, 

 as we may call it, appears at first 

 glance as a simple and plain case of 

 corrasion inlier, the facts that the 

 river there flows parallel to the edge 

 of the Precambric boundary of the 

 Adirondacks and that the rocks dip 

 away from this old land or towards 

 the southwest, indicate the possi- 

 bility of a more complex origin of 

 this inlier. While it might be assumed 

 that since the dip is very small (but 

 2° according to Cushing), it must be 

 easy for the rapidly descending river 

 to overcome the small southern com- 

 ponent of this dip and to reach the 

 Beekmantown beds, the fact that the 

 Precambric rocks appear within the 

 a.ia creek, n.y. Scale" 7 . 5 m. = 1 in. Beekmantown beds may indicate that 

 both Precambric and superjacent Beekmantown rocks formed here 

 an old prominence below the Trenton, which has been cut into 

 in this inlier. 



A plainer and simpler case of an erosion inlier is furnished on 

 the Penn Yan-Hammondsport sheet of New York, 1 where an iso- 

 1 Luther, D. D. N. Y. State Mus. Bui. 101. 1906. 



Fig. 11 Inlier 



limestone 



fooooo . 

 booooJ m 

 |o o| 



f Beekmantown 

 Trenton 



limestone 



along West Can- 



