28 NEW YORK STATE MUSEUM 



fossil has been described and figured in the " Geology of Canada," 

 page loi, as Scolithus canadensis. A very similar or 

 identical form occurs in the Upper Cambrian (St Croixan) Eau 

 Claire sandstone of Minnesota. 



That the Heuvelton sandstone may furnish a valuable building 

 stone is shown in the school building and the Episcopal chapel at 

 Morley. The rock used is ashen gray with a tendency to a rust}' 

 buff stain, and was quarried on the river bank just behind the 

 chapel, the trimmings being from the Hannawa Potsdam quarries. 

 Quarries have also been opened in this rock elsewhere, as at Heu- 

 velton and near Sissonville (locality 32), the latter for road metal 

 and extending downward into the Theresa beds. 



The Heuvelton sandstone varies somewhat in thickness, appar- 

 ently through irregularity of its summit plane, certain upper layers 

 being sometimes present and sometimes absent. It is thinnest at 

 the old mill site below Bucks Bridge (locality 54) where the over- 

 lying beds are thickest, and has its full thickness at the Stony 

 Brook falls (localities 35, 36) where the overlying ledge is thin. 

 (See figure A, plate 9.) At the latter locality there is even some 

 appearance of calcareous (rotten) upper Theresa sediments above 

 the Heuvelton, exposed on the north-south roadway, but too thin for 

 mapping. If correctly so interpreted, this is the only locality yet 

 known on our quadrangle where there remains any trace of the 

 upper Theresa beds that lie above the Heuvelton lentil on the Brier 

 Hill and Ogdensburg quadrangles. They seem otherwise to have 

 been removed by erosion, together often with some portions of the 

 top of the Heuvelton, before the succeeding Bucks Bridge beds 

 were deposited. 



Bucks Bridge Mixed Beds 



The Heuvelton sandstone is succeeded by another white, sandy 

 mass of different aspect, considerably more calcareous, passing 

 gradually upward into heavy, dark, silicious dolomites with only 

 rare sandstone layers, and these in turn becoming more quartzose 

 again as the summit of the group is approached. No complete 

 section is available for measurement, but the total thickness may be 

 safely put at over 50 feet and perhaps nearer 70, though a cursory 

 view of the occasional thin exposures would not at once suggest 

 so great a bulk. 



