510 i : i : a i n a i: i » and si:i:i.v — tin: C a i.c i ii:i:< >i - FORMATION. 



of fossil-bearing rocks interbedded with tbem the difficulty ina large measure 

 disappeared. They can besi be recognized by their relation to the super- 

 jacent and subjacent beds, their lithological differences affording unsatisfac- 

 tory distinctions. 



amount of pure limestone was another surprise. These pure masses 

 are mosl uoticeable in division B; and the fact <>f its great abundance sug- 



3ts the iuquiry whether a portion of the marble lying near the thinks ol 

 the Green mountains may not be metamorphosed Oalciferous. 



A - iou in this immediate connection is that the sandstones and 



sandy limestones of division C and those of the lower part of D gave the 

 name Calciferous to the formation. The fucoids, so far a- we have seen, art' 

 not characteristic of any one division, though they appear abundantly in 

 various horizons of D. Further. Scolithua cannot be regarded as indicating 

 a Potsdam" horizon, as the most abundant display that we have ever seen is 

 to he found at the bottom of division C,six or seven hundred feet above the 

 Potsdam sandstone. 



A great surprise awaited us in the abundance of the fossil forms. The h> 

 and more genera, represented by over a hundred species, was an unlooked- 

 for result. Some limestone hands are packed with fossils; while the sand- 

 stones as well a- magnesian limestones, which at first were thought to he 

 barren, contain both obscure ami distinguishable fossils. The collection we 

 have made is to he regarded rather as a preliminary than a complete one. 

 A wide field for the study of paleontology is opened before u-. Forms 

 that were supposed to <'\i>t only at higher horizons are found to descend 

 more nearly to the primordial zone. 



The discovery of Utica fossils in the .-late supposed to belong to the ( 'al- 

 ciferous simplifies the study of the formation by leaving out one perplexing 

 factor. 



The- almost entire exclusion of the Birdseye formation from the Vermont 

 rocks was a result unexpected. 



lie' exact horizon of the Fort ('a—in rocks seemed a simple problem, and 

 one we set ourselves to solve. Assuming the rock and fossils so like Birds- 

 eye to \>t- Birdseye, it appeared only necessary to find localities where the 

 upper Chazy approaches the Black river; and between would be the rock 

 ami the fossils we were Beeking. Hut in every such Locality we found the 

 Black river directly above the Chazy with no room for the Uirdseye. lint 



we did find other exposures of the Fori < lassie rocks. And at what horizon :' 

 Challenging our belief with a sensation like a violent -hock, there appeared 

 Calciferous below, Calciferous above. These rocks then dropped down to 



the upper member of division J), a fall of 1,000 feel ; and their fauna went 



t" -well the increasing number of the < lalciferou 



