282 Remarks on the Taoojiic System. 



The maintainers of the metamorphic Silurian theory are 

 driven to the following absurdities ; that the Utica slate and 

 Hudson Eiver group of rocks, confessedly only a few hundred 

 feet in thickness, have been so plicated, uptilted, and pressed 

 together, as to fill a country more than thirty miles wide with 

 their strata, at a steep inclination. And, moreover, that the 

 lower members, as the Pottsdam sandstone, calciferous, chazy, 

 and Trenton limestones, and, in one case, the Helderburgh lime- 

 stone unmetamorphosed, are superimposed upon the uptilted 

 and metamorphosed later rocks of the Utica slate and Hudson 

 Eiver group. How came the older reclining in a normal con- 

 dition upon the later ? The one changed, the other unchanged ? 

 Again, how came the upper Silurian limestones to thicken into 

 two thousand feet of material in the distance of twenty-five 

 miles, — in the one case metamorphosed into marble, and in the 

 other case remaining in its usual thickness of a few hundred 

 feet and unmetamorphosed ? 



And, once more, why should the uniform eastward tilt cease 

 with the upper Silurian, and a new^ inclination be imposed upon 

 the Devonian, if Central Massachusetts is but the Devonian 

 metamorphosed ? 



If in Illinois we have the Carboniferous unconformable to the 

 Devonian, upper Silurian, and lower Sihirian, why uuiy we not 

 have the coal measures in Massachusetts and Rhode Island 

 unconformed to the Sub-Silurian ? 



In the Taconic system we have a new volume added to the 

 geological history of the earth, carrying us back into the his- 

 tory of its palseozoa to a new and lower horizon, as remote 

 from the Silurian as it is from the Carboniferous. In its fauna 

 and flora we have the primal forms of the biological alj^habet, 

 and though the generic character of its inscriptions extend into 

 .the Silurian, and, as for that matter, even up to the present 

 time, its specific characters are essentially distinct. 



Note. — Since the foregoing remarks were read, I have 



