IlS NEW YORK STATE MUSEUM 



Feet Inches 



2 Light to dark gray, crystalline dolomite, many 

 nodules of crystalline calcite, often large ; many 

 of the beds have calcareous cement and Aveather 

 porous, crumbly and sandy looking 20 



I Concealed to level of Mohawk 90 



Though this section is very imperfect, yet it gives both the 

 upper and lower contacts of the Tribes Hill limestone with a 

 thickness of 168 feet for the formation in this section. The 

 base is well shown and is distinctly unconformable on the dolo- 

 mite beneath. The Little Falls dolomite has the general char- 

 acters that it shows in all sections, the coarsely crystalline, whit- 

 ish beds above, and darker, finer grained beds below. The base 

 of the dolomite is below the river level, but it is quite certain 

 that the Potsdam is still in place beneath. The Amsterdam 

 sheet, midway of which this section occurs, corners on the Sara- 

 toga sheet at the southwest and is distant only 20 miles from 

 the Saratoga section. On the Broadalbin sheet (north of Am- 

 sterdam and west of Saratoga) Miller finds the Potsdam run- 

 ning all the way across the sheet from east to west. The section 

 differs from that at Saratoga chiefly in that the Tribes Hill 

 formation has come in between the Little Falls and the over- 

 lying Mohawkian. It differs from the Ticonderoga section in 

 that none of the Beekmantown except the Tribes Hill division 

 appears. The section was measured up the creek Avhich comes 

 into the MohaAvk at Cranesville from the north, diverging from 

 the creek up the left-hand road, i mile north of the river. 

 Cumings had previously published the same section though we 

 subdivide somewhat differently and find the thickness of the 

 upper part less than he gives it.^ 



Seciion at Tribes HiU 

 At Tribes Hill, 8 miles west of Cranesville, we also measured 

 the section. The locality is just across the river from Fort 

 Hunter, where the original discovery of the fauna which Cle- 

 land described was made.- The section at Tribes Hill is much 

 less complete than at Cranesville, but we have chosen it as the 

 type locality because of the excellent exposure of the character- 

 istic fossiliferous limestone of the formation Avhich is found 



' N. Y. State Mus. Bui. 34, p. 441. 

 ^Am. Pal. Bill. v. 3, no. 13. 



