GEOLOGY OF THE VICINITY OF LITTLE FALLS 31 



A thickness of 4 feet of black limestone with shale partings, 

 -quite like that at Ingham Mills, is exposed mile to the southeast 

 at the brook and road crossing near the east edge of the map. 

 The Trenton appears directly above, but the full thickness and 

 the Low vi lie below do not show. 



Away from the vicinity of Ingham Mills the formation has been 

 noted at but one locality within the map limits. By the road 

 from Diamond hill to Gray, nearly 4 miles beyond, and slightly to 

 the west of north of Diamond hill, the Lowville limestone is 

 hown and capped by a 3 foot thickness of solid, black limestone 

 with the Black river character and fauna. The summit does not 

 show. 



All the other contacts within the map limits, and they are 

 many, show the Trenton resting directly on the Lowville, with the 

 exception of one a mile north of Middleville, which discloses a 

 thickness of 1 foot of black, calcareous shale between the two. 

 We have therefore nearly as marked evidence of irregularity and 

 interruption of deposition above the Lowville as there is below. 

 There is to be added to this also as significant, the variation in 

 thickness of the Lowville itself, and the fact that the nearly com- 

 plete lack of a marine fauna in it would likely indicate local and 

 restricted deposition conditions, rather than those of the open 

 ea. The marine fauna would certainly have been preserved 

 in the rock had it been there. 



Trenton limestone. The larger part of the thickness of the 

 Trenton within the map limits is constituted of a gray, thin 

 bedded, semicrystalline limestone, often a mass of fossils or of 

 fossil fragments, locally called shell rock. With this are layers 

 of dark blue limestone, sometimes rather massive but oftener 

 thin, and with a shaly tendency. These are sometimes very full of 

 fossils also, but usually contain them much more sparingly than 

 do the gray beds. In general the gray beds are more prominent 

 in the lower, and the dark blue in the upper part of the formation. 



Upward, the gray layers die out entirely, and the limestones are 

 succeeded by a considerable thickness of alternate limestone and 

 hale bands of blue black color, which form a lithologic transition 



