32 NEW YORK STATE MUSEUM 



similar results.^ Contacts are few on the Saratoga quadrangle, but 

 to the north of the village the basal Potsdam conditions are well 

 shown for a distance of 4 miles along the Potsdam margin; and for 

 a mile along the Hudson just below Corinth exposures of this 

 horizon are excellent. The Precambric surface on which the Pots- 

 dam rests is irregular. The more resistant bands of the Grenville 

 and the igneous rocks stand above the mean level, as hillocks or 

 ridges, while the weaker rocks are worn away to valleys or basins 

 below mean level. Potsdam deposition began in the depressions, 

 and as the sand accumulated it finally overtopped the elevations. 

 There are differences of level of at least 75 feet, and probably more. 

 Assuming that the conditions of this surface on the northwest 

 and the southeast (Thousand Islands and Saratoga regions) are 

 substantially the same, as the evidence indicates, and that the sur- 

 face on the southwest (Little Falls-Remsen) is much smoother, it 

 would seem probable that in the opposite direction, on the north- 

 east, it should be rougher. In that direction we lack the detailed 

 work which might render the matter certain and can merely state 

 that the impression given us by our reconnaissance work on the 

 northeast is that it is rougher. We have seen Precambric hills 

 which project up into the Potsdam to the distance of 200 feet. 

 From the data at hand we therefore conclude that the Precambric 

 surface under the Potsdam is least smooth on the northeast 

 (Clinton county), and that it steadily increases in smoothness 

 toward the southwest. The northwest and the southeast are about 

 equidistant from these and should be expected to show about equal 

 character of surface, as they do. 



CAMBRIC PERIOD 



General statement. The formations of Cambric age belonging 

 to the western basin and found within the mapped district, are the 

 Potsdam, Theresa and Little Falls formations, the Potsdam a sand- 

 stone, the Theresa a series of passage beds of alternating sand- 

 stone and limestone or dolomite, and the Little Falls a dolomite 

 formation. Between the Theresa and Little Falls in the near 

 vicinity of Saratoga is a more calcareous formation which we call 

 the Hoyt limestone, which is probably best regarded as an upper 

 member of the Theresa formation. 



According to prevailing present-day classification, these forma- 

 tions are of Upper Cambric age. They also belong in the new 

 system, Ozarkic, which Ulrich is proposing to establish between 



1 N. Y. State Mus. Bui. 153, p. 50-52. 



