22 NEW YORK STATE MUSEUM 



those in the Hudson valley. Sands and gravels for building, engi- 

 neering and other uses also occur widely. Special grades of molding 

 sand are found in the Hudson valley, glass sand occurs in limited 

 deposits; fire sands, filter sands and other kinds also are represented. 

 Peat is a common material in many of the swamps and shallow 

 lakes, but has not been utilized to any extent. Calcareous marl 

 has the same distribution and is also little developed. Diatomaceous 

 earth abounds in some of the Adirondack lakes as a recent accumu- 

 lation. 



