212 Geology of the Lakes and the Valley of the Mississippi. 



mens is, to purposes of geological classification, I need not remark. 

 The geology of a country must be studied in the open air. I 

 found by comparing the limestone of the western part of Lake Erie, 

 with a specimen of English Has, in the cabinet of Major Whiting at 

 Detroit, that it differed less in its external character from the Eng- 

 lish, than from the same rock at the cataract. The English speci- 

 men, being of the sort used for purposes of lithography, was of a 

 finer texture and brighter yellow, while the American, was of a drab 

 or pale buff. Every one is familiar with the difference between the 

 English lias, compact and earthy as it is, and the lias of Mount Jura 

 and district of Vosges, which, if not crystalline, is at least granular, 

 and resembles the limestone at the cataract in this respect ; yet eve- 

 ry one admits its title to the appellation. 



No one yields a more ready deference than I do to the opinions 

 of European geologists, especially the English, in matters within 

 their personal cognizance. The science has not passed its maturity 

 any where — here, it is still in its youth. But an implicit accordance 

 with the views of foreign geologists, in matters about which they have 

 not an equal opportunity to judge from personal observation, would 

 be prejudicial to that freedom and boldness of enquiry, by which alone 

 we shall be led to true conclusions, in respect to the natural history of 

 our continent and thus contribute our proportion to the general stock 

 of accurate knowledge ; and this contribution must be made without 

 waiting till it has received the stamp of foreign approbation. We 

 may get our principles from abroad, but their application must be by- 

 persons on the spot. The Austrian armies were invariably beaten 

 while their movements were directed, not by the general in the 

 field, but by the cabinet at Vienna. Had Mr. Conybeare ridiculed 

 the idea of our having the lias, after he had ascertained by personal 

 examination that our formations from the granite to the new red 

 sandstone inclusive, occur exactly as they do in England, and that 

 the sandstone supports beds of limestone and shale in layers con- 

 taining fossils, identical, as far as they have been examined, with 

 those of the lias, I should have paid as much respect to his opinion 

 as to that of any other eminent geologist. But to him America is, 

 in a geological point of view, terra incognita. It is comparatively 

 so even to ourselves. I should dispute the competency of any 

 man to decide the present question, who had not, in person, inves- ■ 

 tigated the country to which it belongs, although he had even seen 

 the limestone at the cataract if he had seen no more. 



