SIXTH REPORT OF THE DIRECTOR I909 1 53 



ing, that red clay is now forming as a widespread deep sea deposit 

 particularly in the Pacific, but these clays are practically confined 

 to the neighborhood of volcanic regions and they are considered to 

 be due chiefly to the deposition of volcanic dust. Obviously this 

 mode of origin will not apply to the Vernon red shale because it 

 is a terrigenous rather than a deep sea deposit. Some red mud 1 

 is now depositing locally as in the Yellow sea and along the coast 

 of Brazil, but it is being derived from moist, tropical regions where 

 conditions are favorable for spontaneous dehydration of the ferric 

 oxid. Such dehydration of ferric oxid under conditions of warmth 

 and moisture is well known to account for the deep red color of 

 laterite, the soil so: characteristic of the tropics, and which colors 

 the river silts. The climatic evidence is opposed to such an origin 

 of color in the Vernon red shale. 



Applying Barrell's view, the iron in the Vernon shale was present 

 at the time of deposition in the peroxid form, but hydrated and 

 therefore not red, and the dehydration with resulting red color was 

 largely due to great pressure and moderate temperature in the con- 

 solidated and deeply buried sediment, since hydrated ferric oxid 

 readily gives up its water under such conditions. This dehydration, 

 combined with the finely divided and diffused ferric oxid, the 

 writer believes accounts for the red color of 'the Vernon shale. 



Very commonly stains of yellowish to yellowish brown oxid of 

 iron may be seen along fractures in both the red and green shales, 

 and these are clearly due to the hydration of some of the ferric 

 oxid since exposure to the weather. 



Origin of the green spots. As already stated one of the 

 striking features of the Vernon formation is the presence of 

 numerous light green spots scattered through the dull red shales. 

 So far as tested the material of these green spots is precisely the 

 same as that in the green shale beds in the formation. The spots 

 range in size from a fraction of an inch to several inches in diam- 

 eter. They are mostly spheriodal to flattened spheriodal and seldom 

 irregular. When flattened the long axes lie horizontal thus sug- 

 gesting that the flattening has been due to the pressure of overlying 

 strata and this since the spots were formed. The green spots are 

 nearly always in sharp contact with the surrounding red shale but, 



1 " Mud is a mixture of minerals in a state of extremely fine mechan- 

 ical subdivision, but not chemically decomposed, thus differing from 

 clay." Scott's Geology, 1907 edition, p. 267. The Vernon shale is essen- 

 tially a hardened mud. 



