582 EDWARD SAMPSON 



areas. The silica in many sections is amorphous, as in the 

 case of the green cherts. In many thin sections of the second 

 type of chert and of the red beds of the third type radiolarian 

 tests can be clearly seen. The tests are of clear quartz. The 

 radiolaria are of extremely simple structure; none of them show 

 spines, and it seems improbable that they ever possessed any. 

 The commonest forms are spherical. Many have a clear center 

 and consequently show no shell. They range from 0.20-0.30 

 mm. in diameter. Others are annular in section and about 

 the same size. The central part of these forms is filled with 

 opaque jasper. In the shales associated with the thin beds of chert at 

 islands off Gull Island in Badger Bay, there is a profusion of forms 

 having an elliptical annular section varying from 0.15 x0.20 mm. 

 to 0.30 x0.50 mm. besides very abundant smaller circular forms. 

 In these shales the radiolaria are preserved in great perfection, the 

 boundaries being exceedingly sharp. Only one individual was ob- 

 served having a slight protuberance and none were observed with 

 any spines. 



One occurrence each of the interstitial and of the heavy bedded 

 jasper give evidence of diffusion phenomena having taken place 

 while the silica was in a gelatinous condition. This is best illus- 

 trated by the jasper of the Sweeny manganese prospect at Fortune 

 Harbor. Here 30 feet of jasper is to be seen, which lies between 

 70 feet of pillow lava and a tuffaceous sandstone probably at least 

 50 feet thick. About 15 feet of this jasper is manganif erous ; 

 an aggregate sample of pure unweathered jasper yielded 5.16 

 per cent Mn. This manganese has been further concentrated on 

 joints. 



The manganiferous and nonmanganiferous jasper of this locality 

 show features which are interpreted as having been formed in 

 gel. The most striking features are found in the nonmanganiferous 

 portion illustrated in Figures 2, 3, and 4, In Figure 2 the dark 

 areas represent opaque jasper, and the clear areas silica with cloud- 

 Hke specks of iron oxide. These are shown in Figure 3 which is a 

 portion of the same field as Figure 2. It is to be noted that all 

 areas, regardless of size or shape, are surrounded by a clear band 

 about 0.004 mm. thick and outside that a dark band somewhat thin- 



