GfiOLOGY Ot tHfe WfeSt POINl" QUAbtiAMGLfe, NfeW VoRK ^I 



liminary statements and discussions of particular formations or 

 special problems have appeared. These were all inspired by and 

 directed along the lines developing with the new studies just 

 described. It is needless to say that such formational studies as 

 those on the Cortlandt series by Rogers and the Manhattan schist 

 by Fettke are the most detailed ever made on these formations and 

 they are accepted as sound both in observation and interpretation. 

 The remaining important formations deserve similar special 

 treatment. 



The bulletin on the Geology of the Catskill Aqueduct" contains 

 some of the newer geologic developments from the investigations 

 of the Catskill water supply project; but the purpose of that study 

 did not yield to much elaboration of purely scientific discussion, 

 such as detail of origin and structural habit and age or correlation 

 of geologic formations. 



As investigation and exploratory development progressed, it came 

 finally to be appreciated that the West Point quadrangle contains 

 the most suggestive and critical ground of the whole region and 

 that it could be made a key study for southeastern New York. On 

 this account the West Point quadrangle was selected as the one to 

 receive earliest publication rather than the Tarrytown quadrangle, 

 on which work was first begun and whose areal map has been in 

 manuscript form for several years. 



On the north side of the Highlands the Poughkeepsie quadrangle 

 includes patches of the Highlands rocks and great areas of the 

 Poughquag-Wappinger-Hudson River series of sediments. This 

 district has been described and mapped by Clarence E. Gordon.^" 

 It is in some ways a critical district. Within its borders the Hudson 

 river slates seem to transform gradually into highly metamorphosed 

 schists in passing eastward until they can not be distinguished in 

 appearance from the Manhattan schist of the south side. Mr Gor- 



Kemp, James F. Geological Problems Presented by the Catskill Aqueduct 

 of the City of New York. Jour, of Canadian Min. Institute, 14:472-78 

 (1911). 



Kemp, James F. The Storm King Crossing of the Hudson River by the 

 New Catskill Aqueduct of New York City. Am. Jour. Sci. Sen IV, 35:1-11 

 (1913). 



Ridgway, Robert. The Hudson River Crossing of the Catskill Aqueduct. 

 Jour, of the N. E. Water Works Assn., v. 25, no. 3 (1911). 



Rogers, G. S. Geology of the Cortlandt Series and Its Emery Deposits. 

 Annals of the N. Y. Academy of Sci., 21:11-86 (1911). 



Stewart, Charles. The Magnetite Belts of Putnam County, N. Y. School 

 of Mines Quar.. 29:283-94 (1008). 



• N. Y. State Mus. Bui. 146. 



^'' The Geoloaiy of the Poughkeepsie Quadrangle. C. E. Gordon. N. Y. 

 State Mus. Bui. 



