1893.] NEW YORK ACADEMY OF SCIENCES 109 



DIVISION 3, OR BRETONIAN STAGE. 



a. Black shales alternating with dark gray shales. 

 h. The same as the last, but finer, 



c. Black carbonaceous shales. 



? . Same as the last, fauna unknown. 



d. Similar shales, with a few sandy seams. 



In Band b of Division 1, has recently been found a consider- 

 able fauna of Lower Cambrian age. Bands c and d of the same 

 division contain the Paradoxides or Middle Cambrian fauna, 

 while Division 2 and part of Division 3 appear to correspond 

 with the Upper Cambrian of the United States. The upper 

 part of Division 3 is of Lower Silurian age. 



OccuEREiscE OF THE NoDULEs. — The phosphate nodules occur 

 at Hanford Brook, near the eastern end of the southern basin, 

 in Division \b, which is here subdivided into the following 

 zones : 



1. Dark gray sandstone, - - - 40 feet 



2. Dark gray sandy shales, - - - 50 " 



3. Hard, purple streaked gray sandstones, 30 " 



4. Olive gray shale, - - - - 30 " 



5. Gray sandy shale, - - - - 20 " 



In Zone 2 there is a layer of nodules about 2" thick, and they 

 also occur scattered through the hard sandstones of Zone 3. 

 They are of considerable importance to the palaeontologist, as 

 it is chiefly in and near them that the Lower Cambrian fossils 

 have been found. 



Description. — The layer in Div. ]6' consists of small, round 

 or oval nodules, averaging about ^" in diameter, black and 

 comparatively soft, and set in a matrix of soft, green, coarse- 

 grained sandstone, which fades out iiTCguhirly into the finer 

 gray sandy shales. Those of Div. 1/;^ are larger, more irregular 

 in shape, and much harder, and do not break out of their 

 matrix as do the smaller ones. The latter have almost always 

 a trilobite test, or a number of trilobite fragments, at or near 

 the centre ; the larger ones are generally barren of trilobites, 

 though such as do occur in this zone are mostly associated with 

 them. These nodules are conspicuously seen on the surfaces of 

 the great blocks ot sandstone which have fallen down fi'om the 

 steep bank of the brook ; they are also, however, sparsely 

 scattered all through the mass of the rock, and in the upper 

 part are more numerous, and are often fused and run together 

 in masses of larger size, uj) to 3" or 4" in diameter. 



