18^6.] The JYew York System. 199 



says that potatoes which were grown upon a clay soil were most 

 ciffected. Another can see no difference, the disease appearing 

 upon all kinds of soil alike. If observations were directed to one 

 variety, or single varieties, and the disease with its symptoms 

 and severity carefully noted, as they appeared upon different 

 soils, more light would be thrown upon the cause of the dis- 

 ease, as well as upon the peculiar requirements of varieties of the 

 potato. 



THE NEW YORK SYSTEM. 



It has been recommended by the most eminent geologists of 

 Europe, to avoid in geological names, or in geological nomen- 

 clature, those words which may be regarded as hypothetical. 

 Hence the word transition has been disused or gradually dropped, 

 and many other changes in names have been effected on similar 

 grounds. In consequence of the adoption of the recommenda- 

 tions of geologists in these particulars, other names have been 

 employed which express a general fact, and hence instead of at- 

 tempting a classification proper of rocks and formations, a name 

 simply has been given to a series which was derived from some 

 place where the series was well developed. This plan of naming 

 rocks has been extended also to the sub-divisions. The Silurian 

 system for example, is a series of rocks well developed in Wales 

 and the adjacent parts of England. It is a term derived from Si- 

 lures; an ancient race of Briltons who inhabited this part of the 

 kingdom. The system being established it may then be applied 

 to a series of rocks of the same period in different parts of the 

 world. As the relations of the Silurian series are known, we 

 may at once recall to our minds the relations also of a series of 

 the same age in any other part of the world; the age of the series 

 being determined by their organic remains, or by their position. 

 It appears to us however, that we need not adhere strictly to the 

 use of the term Silurian, when there is a considerable deviation 



