PALEOZOIC ROCKS OF THE CANTON QUADRANGLE 33 



conjunction with the valley of the brook produces a deep reentrant 

 in the Ogdensburg front. A second similar reentrant is formed 

 by the coincidence of the Grass River valley with a second similar 

 low anticline that brings up the basal Bucks Bridge at Madrid depot 

 (locality 7; see previous, page 30). A third reentrant is developed 

 along the Trout brook depression, with its Dailey Ridge tributary; 

 while the Raquette valley is the occasion for a fourth. It will be 

 seen by the map that these sinuosities aline well with the ins and 

 outs manifested by the outcrops of the lower formations, and that 

 finally they all bear some relation to the belts of Precambrian rocks 

 that pass under them.^ See map in Museum bulletin 185. 



In the exposure at the Hewittville lower mills (locality 23) 

 described on page 34, the lowest four and one-half feet are consid- 

 ered to belong to the division just defined. 



To the already mentioned gastropods and fucoids (Palaeophy- 

 cus) of the Bucks Bridge fauna, which are even better displayed 

 in the upper division than below, these upper beds contribute a 

 more significant element in a little graptolite from the highest layers 

 of the formation at locality 12 on Trout brook just north of the 

 Rutland bridge. Concerning our provisional reference of the speci- 

 mens to his Deep Kill species Dictyonema rectilinea- 

 t u m,^ Doctor Ruedemann writes : " The Dictyonema is, in the best 

 preserved specimen, finer than the typical D. rectilineatum, 

 though having all the characters of it. It has 18 branches in 10 

 mm against 12 to 14 of that species. Another fragment has 14 

 to 16. Also the branches themselves are finer; otherwise, however, 

 they are alike in form. Probably these dififerences are due to the 

 preservation in difit'erent matrices." But the species may also be 

 compared with D. sociale of Salter, generally made' a synonym 

 of D. f 1 a b e 1 1 i f o r m e, a widespread horizon-marker that Doc- 

 tor Ruedemann has recognized^ in the Schaghticoke shale of the 

 Hudson valley, below the Deep Kill. 



Hewittville beds.* Capping the Bucks Bridge formation on the 

 west bank of the Raquette river just below the concrete dam of 

 the lower mills at Hewittville (locality 23) and so just east of this 



^ Geol. Soc. of Amer. Bui. 26, p. 287-94, " Post-Ordoviclan Deformation 

 in the Saint Lawrence Valley." 



' N. Y. State Mus. Memoir 7, p. 607, fig. 29; pi. 3: fig. 9, to. 



' N. Y. State Mus. Bui. 69, p. 934-58. 



''This name is not intended in a formational sense, but is u'^^d here for 

 convenience only. 



