ANCIENT LOESS-LIKE DEPOSITS 569 



in which the New Red sandstone of Britain was accumulating, 

 partly at least as a sand-dune formation. (Lomas-29.) 



Palccozoic Loess-like Deposits. Unstratified deposits of fine 

 and uniform-grained rocks, free from organic remains and having 

 a general loess-like character, are not uncommon in Palaeozoic and 

 later formations. As already noted, the Nunda or' Portage sand- 

 stone of central New York, a formation of Upper Devonic age, has 

 the characteristics of a consolidated loess. This is especially seen 

 in the Genesee A'alley near the type locality, where the rock for 

 considerable thicknesses shows* a lack of stratification and a fine- 

 ness and uniformity of grain strongly suggestive of these charac- 

 ters in Pleistocenic loess. There is a notable absence of fossils, ex- 

 cept vertical tubes {Fucoidcs verticalis) , similar in many respects to 

 those found in more recent loess. The rock, furthermore, splits 

 with a decided vertical tendency, forming slabs of varying thick- 

 ness. This deposit was probably not formed far from the sea, and 

 was succeeded by normal marine sediments. 



Certain portions of the St. Peter sandstone also appear to be 

 of this character, as shown by the fineness and uniformity of grain, 

 absence of stratification and splitting into vertical slabs. Much of 

 this sandstone appears, however, to be of dune origin, subsequently 

 in part reworked by a transgressing sea. 



Many other Palaeozoic formations will probably prove on fur- 

 ther study to have a loess-like origin. This appears to be especially 

 so in the case of those fine-grained, nonstratified deposits which are 

 associated with continental formations of another type, such as 

 fluviatile beds, dune deposits, salt and gypsum beds, etc. Often such 

 loess-like deposits are of a red color, owing to the presence of iron 

 in the ferric oxide stage. The red Vernon shale of eastern New 

 York apparently furnishes a good example of this type of deposit. 

 This formation is of mid-Siluric age, and marks in the opinion of 

 many the beginning of a period of widespread continental sedimen- 

 tation under arid climatic conditions. This red shale in the Syra- 

 cuse area is followed by the salt deposits of Salina age. 



The red color of this formation is due to the presence of de- 

 hydrated ferric oxide, of which 2.25 per cent, occurs in the entire 

 mass. Ferrous oxide of iron is present in small quantities (0.75 

 per cent.) (Miller-34 :/t/). The iron is distributed in small quan- 

 tities, but with great uniformity throughout the mass. It is not im- 

 possible that, as Miller argues, the color was not originally red, but 

 yellowish, the iron being in the form of the hydrate. Subsequent 

 dehydration would produce the red color. In this connection it 

 is interesting to kjiow that tlie ordinary yellow loess commonly con- 



