1/ C Y Th« (our -digit numban in the column on ih« left give lh« lotitudc and longilud* of (he 

 l\ C I louthcoil corner of eoch one degree-quodrongle. Eoch one-degree quadrangle ii divided 

 into 30-minute quadrangle*, numbered oi in (he dlogfom to the right The columni of Iheie loblei 

 give I A- fnimmum temperature, B- moaimum temperature, C' number of yeart, D' number of doyt. 



DEPTH ZONE 



25 



