GENERAL STRATIGRAPHY OF THE AREA 



289 



Upper Beekiuiuitowu (Ogdensburg) dolomite. 



Uuconformity. 

 Bucks Bridge (approximately Tribes Hill) mixed beds. 



Unconformity. 

 Heuvelton ("Twenty-foot") white sandstone. 

 Theresa mixed beds (as restricted by Ulrich). 

 "Upper Potsdam" (Kee.seville?) white sandstone. 

 Typical Potsdam sandstones (mostly red). 



Tlie name Heuveltou is introduced, with Professor Ciisliing's consent, 

 lor the heavy white sandstone, recognized independently by him and by 

 the writer,*^ which from its resistant nature has proved the most valuable 

 stratum on the Canton quadrangle for the solution of the stratigraphic 

 problems injected by the obscuring drift-cover. It is cluii-acterized by 



i. O njt/es 



guc £, 



%^h^A r 



TBuck's Tiridje. 

 H&u vel -tot] 

 The r&sa 

 Whi-f-e. 'Pois<:/<nrn 

 PrecamLri a q 





FioiiRE 2. — Folded Paleozoic Rorlcs on Ogdenshiirg and' Canton Quadrangles 



Scolitkiis canadensis and by large gastropods suggestive of an Ordovician 

 age, but seems conformable to the Theresa; the exact age is still in doubt. 

 Tbe overlying beds, totaling some -"lO to '10 feet on the meridian of Can- 

 ton, are characterized by PaUeophycas heverleyensis and a lower Beek- 

 mantownian or Tribes Hill fauna; but as they differ lithologically from 

 the beds of that formation in tlio Mohawk Valley and exact equivalency is 

 not yt't ))ro\ed, the temporary ilesignation Bucks Bridge is here retained. 

 'V\\v (listi'ibution of these rocks on the Canton map is shown in figure 3. 

 In total absence of exposures it has been impossible to carry the Pots- 

 (l;ini sandstones ('()iitinuously across the sheet in figure 3, though present 

 in various outliers. Tbe upper layers may extend thinly across beneath 



tbe drift, as contciK 



Professor Cnshint;'. but tliere .seems liardlv 



" Uc|ii)rt ol' 1 liicctiji- (>r N. V. State Museum t'(jr lltl.'!. |)i). (11, t)4. 



