Ij6 NEW YORK STATE MUSEUM 



reddish tinge which is due to the presence of some finely divided 

 hematite scattered through the cement. There is a relatively large 

 amount of pyrite present, together with rather well-rounded grains 

 of quartz. 



A noticeable feature of the occurrence, indicating the conditions 

 under which deposition took place, is the presence of the gray spher- 

 ules in the filling of mudcracks in the underlying shale. It is quite 

 clear that, whatever their subsequent history, these spherules were 

 formed, as such, when the oolitic layer was deposited upon the 

 cracked surface of the underlying muds — obviously under very 

 shallow water conditions. 



In thin section the oolite shows pale grayish green spherules, 

 each one composed of many concentric shells inclosing, usually, a 

 well-rounded grain of quartz (plate i, figures i and 2). 1 This green 

 mineral shows the cross of aggregate polarization and, in general, 

 behaves like chamosite, to which species it was provisionally assigned 

 in the paper last referred to. 2 



While spherules are often isolated, they more commonly coalesce 

 to some extent, different nuclei having the outer layers of their 

 shells in common (plate 2, figures 1 and 2), and it seems clear that, 

 while the deposition of the shells began during the free movement 

 of the nuclei, the process was completed only after the latter had 

 come to rest. Moreover, the frequent bent and twisted shape of 

 the shells strongly suggests a somewhat soft, jellylike condition 

 during their formation (plate 3, figures 1 and 2). 



In addition to the spherules, the sections contain a good deal 

 of fine, angular quartz, rhombohedra of a carbonate, and irregular 

 grains of pyrite. A few fossil fragments are present, in part cal- 

 careous and, in part, silicified, while frequent pale-brown, isotropic 

 fragments, occurring scattered at random through the rock, or 

 sometimes as nuclei of spherules, are unquestionably of the same 

 nature as those occurring in the Wabana, N. P., ores, shown by 

 Hayes 3 to be derived from lingulae and, probably, to be the source 

 of the phosphorus of the ores. It may be added that the gray oolite 

 under consideration has many features in common with certain 

 varieties of the Wabana deposits, which have been described in 

 detail by Doctor Hayes in the paper cited. 



1 For the accompanying photomicrographs, the writer is indebted to the 

 kindness of Mr W. E. Cockfield, fellow in geology in Princeton University. 



2 Types of Ore Deposits, p. 48. 



3 Hayes, A. O., Wabana Iron Ore of Newfoundland: Memoir 78, Geol. Survey 

 of Canada, p. 40 and 57, 19 15. 



