CHAPTER II 

 HUDSON RIVER CANYON 



This is a special study of the Hudson river gorge^ based upon 

 explorations by borings at the several proposed crossings. Alto- 

 gether 226 preliminary borings were made on 14 cross sections. 

 The most important lines of borings are located at seven different 

 points on the Hudson [see location map] . Four of them are in the 

 vicinity of New Hamburg, lying not more than a couple of miles 

 north and south of that village, while three others are located within 

 the Highlands. [See comparative geologic study in following 

 chapter.] The chief basis of information on all but one of these 

 lines is the wash rig, a contrivance as already pointed out that gives 

 rather incomplete data [see Relative Values of Data, pt i]. On 

 this account it is not possible to give the true bed rock profiles of 

 the river canyon even approximately except at one location, i. e. 

 the Storm King— Breakneck mountain line. An occasional diamond 

 drill hole has been put down on some of the others and this has 

 been done systematically at the Storm King location in a persistent 

 effort to determine the gorge profile and bed rock condition. 



The work already done has proven that in the Hudson at least 

 the wash rig borings give wholly unsatisfactory profiles. The holes 

 do not penetrate the boulders and heavy glacial drift that is now 

 known to fill the canyon. The profiles, however, that were drawn 

 from this sort of data have some value. They indicate that bed 

 rock is still lower and that the finer silts extend down to these 

 depths. In some places there is a heavier filling of 400 to 500 feet 

 below them before the rock floor is reached. 



Wherever the diamond drill has succeeded in reaching rock the 

 formational identification has been made and the geological cross 

 section is a little more complete. As a matter of fact, however, at 

 almost every locality the structural relations are so complex or so 

 obscure that they are still not fully known. The accompanving 

 profiles and cross sections summarize the mass of accumulated data : 



1 Kemp, Prof. J. F. Buried Channels beneath the Hudson and its Tribu- 

 taries. Am. Jour. Sci. Oct. 1908. 26:301-23. Some of the accompanyins: de- 

 scriptions of river crossinp:s follow closely this excellent summary of Hud- 

 son river explorations from Professor Kemp. 



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