Chapter 1 



I'llVSKMiKAl'llV OF THE HUDSON AND CilAMPJ.AIN 

 VALLEYS IN lUOLATION TO THE CONTROL OF GLACIAL 

 riiODUCTS 



PHYSIOGRAPHY OF THE HUDSON VALLEY 



The valh'v of the Hudson river, from the jK)iiit of view of the 

 stream ]»eariiig that name, is a geograi)hic orou}) of drainage 

 sloj)es whose axial trongli, if we except the Adirondack portion 

 of the river, lias a nearly north and south direction, traversing 

 a geologic area of variable structure formed of rocks of widely 

 different ages in its various parts, and having different degrees 

 of toj)Ographic develoi)ment. The order and structure of the 

 rocks of its valley have long been portrayed on the geologic maps 

 of the State, and the contour of the land forms bordering the 

 river are now faithfully delineated on topogTai)hic majis, but the 

 preeise history of the origin of this river has not been determined. 

 The reader must, therefore, be content with a statement of the 

 main facts in the form and cross-section of this valley and it is 

 important that these features should be understood in following 

 any attem])t to unravel the Pleistocene history of the valley, 

 particularly in relation 1o its occupation by the last ice sheet 

 and to the retreat. of that ice from eastern New York and the 

 subsequent invasion by the sea of at least the neighboring Cham- 

 |>laln \alley. 



Foi- Die greater ])ortioii of i(s length, the ITud'SOn valley con- 

 sists of a goige ^^il]li^ a vallev. r>oth the vallev and the fforge 

 vary so greatly in iiiiii(»i- detail fioiii \n)\\\{ (o jioini that it is desir- 

 al)le fii'st lo g(MiciaIi/,c Ihe parts in \vlii( h the valley, as a whole, 

 has something like a chaiMcliM-istic geologic and geographic ex- 

 pression. From (Ills point of view there are four longitudinal 

 divisions of flic llndson valley each widi a landscajKi somewhat 

 fXM-nliar (o ilsclf. 



longitudinal divisions of the Hudson valley. The four segments 

 of the Hudson valley above i-eferi'ed to comprise two regions of 

 mountainous relief and I wo of lowlands, one of the latter beins 

 relatively ronghened by somewhat advnnced dissection. 



