Geology. — On the order of Succession of Rocks. 341 



the coal, No. 11, in the general series, which is about 7,500 feet, 

 we can assert that the geological agreement in relation to 

 mineral structure and succession of rocks between America 

 and Europe, is as 32,500 to 40,000. We shall hereafter show 

 other mineral analogies which raise the scale of agreement of 

 this country with transatlantic geology, and without drawing 

 upon the branches of organic nature. 



In relation to the absence of particular beds of the general 

 series, on this continent, we have many curious instances. We 

 have personally examined a geological line, extending from 

 Boston, in Massachusetts, to Washington, in the District of Co- 

 lumbia — and which we know extends much farther, both north 

 and south, — where the extremes of the geological series meet. 

 At Boston, New York, Philadelphia, Baltimore, and Washington, 

 there are no beds between the primary rocks and the superficial 

 soil. No. 40, usually called diluvium. Of the particular causes 

 which have produced this extreme continuous deficiency, we 

 shall not treat here, and shall only observe, that no deduction 

 can be drawn from this circumstance to support an opinion, that 

 any set of causes has been in operation on this continent, in the 

 construction of the primary, other than those which have pro- 

 duced the primary beds in Europe ; because at one of the 

 points of the geological line we have spoken of — New York — 

 whilst the compact part of the city is built either upon the di- 

 luvium which rests upon the gneiss. No. 2, or upon the gneiss 

 itself; at a very short distance from the city, we find the ser- 

 pentine, No. 4, branching from Hoboken, in New Jersey, under 

 the Hudson river, and superincumbent upon the gneiss ; and a 

 few miles further to the north, the primitive limestone in its 

 proper place, lying upon the mica slate. No. 3. And as in many 

 other instances we find each of the beds of the general series of 

 unequal thickness ; sometimes in thick stratified masses, which 

 taper off to a point and then disappear, to re-appear again at im- 

 equal distances ; so we are not to conclude that deficiencies of this 

 various character are the effect of the absence of causes here, which 

 have operated in other parts ; or that the difference between the 

 state of the geological series of rocks in this and in transatlantic 

 countries, is to be attributed to the action of antagonist causes; but 

 rather hold to the opinion, that these deficiencies are in fact inter- 

 ruptions of continuity, occasioned by the irregular action of the 



