THE ADIRONDACK MOUNTAINS 



47 



the Ordovician period a submergence of the same region set in, 

 reaching a maximum in the middle of the period. Such emergence 

 and submergence are proved by the fact that the early Ordovician 

 strata rest upon a distinctly eroded surface of the Little Falls 

 (Cambrian) limestone. The duration of the emergence, geo- 

 logically speaking, was not very long. Even at the time of maxi- 



FiG. 8 Sketch map of the Adirondack region showing the general relations 

 of land and water during the Cambrian and Ordovician periods. Horizontal 

 lines : land area during late Cambrian time ; cross lines : area of land during 

 the middle of the Ordovician. (W. J. M.) 



mum extent of the sea in the mid-Ordovician (figure 8) the 

 evidence is decidedly against complete submergence of the Adiron- 

 dack region. Occurrence of typical mid-Ordovician (Trenton) 

 limestone and shale in the outlying mass at Wells (Hamilton 

 county) indicates the presence of the Ordovician sea over that 



