PALEOZOIC ROCKS OF THE CANTON QUADRANGLE 39 



toechia apicalis(?)^ of the Fort Cassin fauna. Two or 

 more species of Cryptozoon^ from localities already specified, and 

 a finely branching structure supposed to be a nullipore (calcareous 

 seaweed) from the townline road bridge over Trout brook 2 miles 

 east of Madrid (locality 13), complete the forms collected by the 

 writer on the Canton quadrangle. The higher portions of the 

 formation on the Ogdensburg and Waddington sheets contain a 

 larger number of species and better preserved, yet the forms enu- 

 merated here are sufficient to show in these lowest beds the pres- 

 ence of the Ogdensburg fauna and its near relations to that of the 

 '* division D " Beekmantown or Cassin formation of Cushing.^ 



With the exception of the Crj'-ptozoon layers previously men- 

 tioned, it seems possible that all our exposures fall within the basal 

 10 or 15 feet of the formation, though this base may not be the 

 same at all localities on account of unconformity with the subfloor. 

 This unconformity may be seen on the west bank of Trout brook 

 (locality 12) in the joint faces of the beds, and is emphasized by 

 the discontinuous distribution of the Hewittville calcilutites, as well 

 as by the abrupt lithologic change. At Hewittville the contact zone 

 is rendered conspicuous by being a water-bearing plane with sec- 

 ondary solution and recrystallization, while in the quarry farther 

 downstream it consists of a strong shale parting as before noted. 

 The hiatus corresponds to the absence of at least " division C " of 

 the Beekmantown. 



Possible Trenton Limestone Outlier 



On Thomas Veitch's farm just southwest of the road bridge over 

 Brandy brook (locality 4) may be seen by the roadside large slabs 

 of undoubted Trenton shaly limestone full of finely preserved shells 

 of the brachiopod Rhynchotrema increbescens,* and 



^Hemipronites apicalis Whitfield. See ibid. 8, pt i, p. 239, 

 pi. 7A, fig. 26-30. 



^ The species .described from the Beekmantown formation are C 

 s t e e H, C. wingi, and C. saxiroseum of Seely from the Cham- 

 plain valley (5th Vermont Rep't), C. lachu tense of Dawson from 

 Quebec, C. giganteum of Chaney and C. minnesotense of 

 Winchell (with var. liber tat is) from Minnesota (Shakopee dolom- 

 ite). The columnar form from locality 10 is a new species, Doctor Ulrich 

 says. 



•N. Y. State Mus. Bui. 95, p. 363. 



*Hall (as Atrypa), Pal. of N. Y. 1:146, 289; pi. 33, fig. i3a-h. 

 Rhynchotrema inaequi valve of Schuchert and others, but see 

 U. S. Nat. Mus. Bui. 92, p. 1124-25. Identified by courtesy of Doctor 

 Ruedemann. 



