344 



ANNUAL REPORT SMITHSONIAN INSTITUTION, 192 8 



equally in places where there is not the slightest thread of subterra- 

 nean water, as where there is some, and that in consequence it is 

 useless as an indication of springs. Paramelle's work was based 

 upon the combined geographical and geological conditions of the 

 locality (e. g., ibid., pp. 303, 310, chap. 20) : and he remarks that 

 " la geognosie * * * etre la science la plus propre a fournir des 

 lumieres sur les cours d'eau souterrains." He realized the main facts 

 in the distribution of the water table, and where it could be found 

 at easily accessible depths. He admitted that he had failures, and 

 that therefore his method was not perfect; some failures were in- 



FiGURE 16. — Map and section across a gravel-capped ridge of clay. 

 (Section is along line S — S) 



Contours of 100, 90, 80, and TO feet (lines 9, 8, 7). Gravel areas 

 dotted ; rest clay with a thin wash of pebbles in the soil. I, most 

 likely place for well ; II, less productive sites ; III, dry sites. 

 The base of the gravel is at about the contour of 90 feet on the 

 western, and down in places to 70 feet on the eastern slopes 



evitable, as there may be no sign at the surface of disturbing irregu- 

 larities underground. Paramelle concluded that underlying the 

 country is an impermeable sheet, and that wherever wells reach it 

 they find water. His impermeable surface was not, as he thought, 

 an undulating sheet of impermeable material, but was simply the 

 water table. Though his theoretical explanation was defective he 

 was generally right, owing to his insight and careful study of the 

 district, in his inference as to the position of the water table. 



