l6 NEW YORK STATE MUSEUM 



season along the lines developed last year. Although less time 

 than usual was available for this work, considerable additional area 

 was mapped in both the West Point and Carmel quadrangles, some 

 portions of which have been studied in detail. 



In the discussion of Structural and Stratigraphic Features of the 

 Basal Gneisses of the Highlands published last year in Museum 

 Bulletin 107, the major structural types of the Highlands forma- 

 tions were outlined. As a related problem the chief reasons for 

 doubting the exact equivalence of the Inwood limestone and Man- 

 hattan schist to the Wappinger limestone and Hudson River shales 

 were given. A special effort has been made the past season to 

 follow out all of the more promising lines of field evidence bearing 

 upon this question of stratigraphic succession and correlation. This 

 has led to the tracing of the contact lines of the tongues of crystal- 

 line limestones and schists that project into the Highlands from the 

 south side. If these formations could be followed entirely through 

 the Highlands to the north side, as the earlier maps indicate, it was 

 believed that some direct relationship between these crystallines of 

 the south side and the better known Cambric strata of the northern 

 border could be determined. 



After studying for this special purpose all of the valleys that 

 give such opportunities from the south, it seems necessary to con- \ 

 elude that there is no place in New York where the crystalline 

 schists and limestones characteristic of the southerly areas can be 

 traced through to the northern border. There is always a belt of 

 several miles in width occupied only by the typical gneisses of the 

 Highlands. This line of attack therefore furnishes no conclusive 

 proof. 



Observations made on numerous areas of the Cambric strata of 

 the northern border indicate a much more profound metamorphic 

 change in them in passing eastward from the Hudson river to the 

 Connecticut line. Limestones and schists, that seem to be beyond , 

 question equivalents of the Wappinger and Hudson River forma- | 

 tions, have in that district all the characteristics of the Inwood 

 limestone and Manhattan schist of the vicinity of New York city. 



With such results in two of the lines of attack, it seems necessary 

 to make a more minute study of the Stony Point-Peekskill region, 

 the one district where apparently almost typical Cambric formations 

 occur on the southern border of the Highlands. 



As the mapping of the ancient gneisses progresses it is evident that 

 traces of interbedded limestones belonging to the oldest series of 



