JEFFERSON COUNTY. 



383 



It occurs towards the upper part of the rock, in the shaly layer, while the large one is enve- 

 loped in the thick compact strata. 



But of ail the fossils in the birdseye, the one called the Fucoides dcinissus is the most 

 common and abundant. It penetrates the layers vertically ; branching, or rather inosculating, 

 in its own peculiar way, in the midst of the layer as well as upon its surface. It would seem 

 that it chose its habitat far out in the deep, inasmuch as we find it always in the finest grained 

 of all the Hmestone ; its particles, from their nature, being well adapted to a distant transport 

 from the shores. Tlie annexed figure (94), represents the general arangement in the rock, 

 and its pccuhar inosculations. 





The drawing is a fac simile of this fossil, as it appears in a quarry at Fort-Plain in the valley 

 of the Mohawk, except that it is upon a reduced scale. 



The next figure (95), embraces a fragment of the fossil in its natural size. 



