18 



ANNALS NEW YORK ACADEMY OF SCIENCES 



along lines of faulting give strong character to a map of the Adirondacks. 

 Tectonic valleys characterize the New York City region where the Man- 

 hattan Street depression, the Dyckman Street cross valley (Fig. 14), 

 the Harlem Kiver, and some of the notches of the Palisades owe their 

 position to ancient lines of dislocation. At Saratoga the mineral springs 

 are believed to follow similar lines of displacement. The offsetting and 

 overlapping of ridges resulting from faulting, planation, and later dis- 

 section of a region of dipping alternating resistant and non-resistant 

 beds is illustrated in the Hanging Hills of Meriden and other trap ridges 

 of Connecticut (Fig. 18). 



Geo I. Column 

 Palisade 7rap 

 Triass/c s.s. 

 Manhattan Jeh. 

 fowood 1.5. 

 vrt/ham gn. 



northern New York City 



Fig. 14. — Diagrammatic representation of the essential relief features of northern 

 New York City, with cross-sections showing the underground structure 



The resistent character of the Fordham gneiss, the Manhattan schist, and the Pali- 

 sade trap is noteworthy, as is also the development of the valleys upon the limestone 

 belts. The letters on the diagram refer to the following features : B, Bronx River ; B P, 

 Bronx Park ; D, Dyckman street cross valley ; F, Fordham Heights ; F G, Fort George 

 Heights ; F W, Fort Washington Heights ; F L, Fort Lee ; H. Highbridge ; Ha, Harlem 

 River ; Hud, Hudson River ; P, Palisades ; W, Washington Bridge. 



Folded Mountains. — When the presentation of folded mountains is 

 introduced the teacher may be proud that he can cite examples from this 

 region unexcelled in the entire world. Around Kingston and Catskill 

 the study may be taken up in miniature, but with all the essentials of 

 form. The Little Catskill Mountains make it possible for one in a half 

 day's journey to see an anticlinal, synclinal, and monoclinal mountain 

 and an anticlinal, synclinal, and monoclinal valley, all in close juxtapo- 

 sition to each other. The Shawangunk Mountains and Eondout hills are 

 within easy reach. In western New Jersey Kittatinny Mountain may be 



