1 882.] Vie Loess of North America. 369 



which have thus far been collected in America ; they seem to 

 illustrate the futility of attempting to define satisfactorily varieties, 

 and to warrant their abandonment and the substitution of 

 "forms" varying with the locality, as has been suggested by 

 Professor Nordstedt, of Sweden, and is the practice in the case 

 of the polymorphous species, C. fvtida A. Br., C. intermedia A. 

 Br., and many others. 



A few of the more remarkable forms may still retain a specific 

 name, as var. Oahuensis A. Br., perhaps var. gracilis Allen, and a 

 few others ; or it might even be admissible to bestow a specific 

 name on each constant form as a convenient method of desig- 

 nating its peculiarities. For the present, however, while our 

 knowledge of the American forms is yet so incomplete, we prefer 

 to classify them as above. 



THE LOESS OF NORTH AMERICA. 



THE term loess is a purely provincial one, having been origi- 

 nally applied by the residents of the Rhine valley to a certain 

 comparatively recent formation bordering that stream. It is the 

 anglicized form of the German loss, itself a derivative of the verb 

 Ibsen, to loose or to detach. It was evidently bestowed in allu- 

 sion to the loose texture of that loam-like soil, and, in its present 

 acceptation, is to be regarded as nearly the equivalent of the En- 

 glish loam. 



Historical. — The earliest notice of the loess in America appears 

 to have been in connection with various exploring expeditions sent 

 out by the General Government. That of Lewis and Clark, made 

 between the years 1803-1806, to the Rocky mountains, by way of 

 the Missouri river, called attention to the remarkable character, 

 both physical and lithological, of the bluffs along that stream, 

 but for aught the report contains their true geological position 

 and history were not recognized. Later, the celebrated artist, 

 Catlin, in his letters to England from the Northwest, 1 gives a 

 very accurate and graphic account of the Missouri river bluffs, in 

 which he mentions certain of their remarkable physical pecu- 

 liarities. 



The real geological character of this formation in the United 

 l CatHn's N. A. Jndians, Vol. 1, p. 19, 1876. London, Chatto & Windns. 



