50 [Assembly 



mon centre, and were connected like the ribs of an umbrella by 

 a membranous or horny film. The whole family of Graptolites is 

 extinct, and their fossil remains characterise the older forma- 

 tions, to which they are confined with few or no exceptions. 



(The eastern part of New York and the western part of most 

 of New-England are formed of an enormous mass of upheaved 

 and bent strata of slates, sandstones and limestones, which Dr. 

 Emmons has always maintained to be of lower position and older 

 date than the Potsdam sandstone ; and he has described them in 

 his reports as the Taconic System. This range of rocks con- 

 tains very few or no fossils in most localities, and geologists 

 have been obliged to examine it without the aid which fossils 

 would have given in explaining the relation and true posi- 

 tion of its confused and contorted strata. The general con- 

 clusion has been that this series of strata is not a separate .and 

 distinct one, but merely the eastward extension of the rocks 

 older than the Medina and Clinton groups, changed in char- 

 acter or " metamorphosed '' by the efi'ect of heat and pres- 

 sure. But some recent discoveries, in a few localities of this 

 " Taconic " range, have brought to notice fossils from them, so 

 differing from forms previously known, as to indicate that these 

 strata are indeed a distinct and separate series. The opinions of 

 some of the most competent geologists seem therefore inclining 

 to the views of Dr. Emmons ; and there seems to be a probability 

 that it may be yet recognized as an older series of rocks, lying 

 beneath the Potsdam sandstone, and preserving in its fossils the 

 relics of the earliest period of living things. Others, however, 

 adhere to the belief that these fossils show merely a local develop- 

 ment of a portion of the Hudson-river group, with a peculiar set 

 of fossils. There are great difficulties as yet in reconciling the 

 apparently contradictory appearances which these rocks present ; 

 and the question is so obscure, that difierences of opinion may 

 well exist till further observations are made.) 



The Hudson-river group is covered in many places by a bed of 

 conglomerate rock, made up chiefly of coarse sand and worn and 

 rounded pebbles of quartz.. Being well developed in Oneida 

 county south of Utica, it has received the name of the 



