General Strata. 361 



In this nomenclature, I omit many of the numerous gene- 

 ral strata, given by Europeans, specimens of which may be 

 found in this country. But the same European geologists 

 would, in my opinion, consider the omit,ted strata as beds or 

 Varieties, even in their own country, after examining them 

 here. The numerous primitive ranges in Europe cut up the 

 strata into such limited portions, that it is difficult to distin- 

 guish between what ought to be treated as a bed or a variety, 

 and what as a general stratum. Here we have no general 

 stratum which cannot be traced from one hundred to five 

 hundred miles. It was said by De Luc, that the general stra- 

 ta must be settled in America, where nature seems to have 

 executed her works upon an enlarged scale. 



Probably future geologists will find it convenient to divide 

 the Lias and Third Graywacke into several general strata. 

 But it is the opinion of several American geologists who have 

 visited Europe, and of two European geologists whom I have 

 accompanied to some of our important localities, that both 

 of these strata and the two interposed, are comprised in the 

 Oolitic formation of the English. It is certain that the es- 

 sential characters of the upper and lower layers of what I 

 have called Third Graywacke and Lias, are very accurate- 

 ly given by Philips and Conybeare as layers of the Oolitic 

 formation. Therefore, to follow these eminent geologists, 

 we must put the whole vast range of the Allegany and Cats- 

 kill Mountains in the same general stratum, and all other vis- 

 ible rocks, excepting the saliferous, between the River Hud- 

 son and the Rocky Mountains. But we must treat some 

 minute beds of a few yards in extent, on the east side of the 

 Hudson, as general strata. 



According to the nomenclature here adopted, the Lias, 

 Geodiferous limerock, the Cornitiferous limerock, and the 

 Third Graywacke, occupy, as uppermost rocks, more than 

 half of the great states of New York, Pennsylvania, and Vir- 

 ginia, and nearly all the states of Ohio, Indiana, Illinois, Ken- 

 tucky, Tennessee, and the Michigan Territory. If we adopt 

 the European nomenclature, we must treat of this vast ter- 

 ritory under the Oolitic formation, though no Oolite has ever 

 been found in it — the Saratoga Oolite being confined to the 

 transition sandstone of Werner, (our Calciferous sandstone.) 

 For these and other reasons, I prefer continuing the use of 

 descriptive terms which cannot mislead ; and leaving to 

 others the business of giving precise technical names. 



Vol. XIV,— No. 2. 20 



