108 TRANSACTIONS OF THE [FeB. 23 



other portions of the western Adirondack region. A second 

 contribution on the petrograj^hy of the region will shortly 

 follow. 



Hamilton College, Clinton, N. Y. 



ON PHOSPHATE NODULES FROM THE CAMBRIAN OF 

 SOUTHERN NEW BRUNSWICK. 



BY W. D. MATTHEW. 



Introduction. — Nodules and beds of phosphatic material are 

 best known in the Cretaceous and Tertiary formations, but they 

 also occur in many places in strata of Cambrian and Silurian 

 age. The deposits of these older rocks are sometimes of economic 

 importance, and are always interesting, both on account of the 

 various theories of their oi'igin, and because they are generally 

 considered as due, directly or indirectly, to organic life. 



To account for the little changed phosphate deposits of the 

 Cretaceous and Tertiary, has proven a matter of no small 

 difficulty, and many hypotheses, more or less plausible, have at 

 different times been advanced. With the older deposits thei*e 

 is even greater difficulty, because they are usually so altered 

 that their original structure is pretty well obliterated. 



Division of the Saint John Group. — Those described here are 

 from the St. John Group of Southern New Brunswick, a series 

 of gray slates, shales, and sandstones, mostly of Cambrian age, 

 which formerly filled the bottoms of a number of long, parallel, 

 northeast and southwest valleys, but which have been mostly 

 swept away or covered by later deposits, except in the southern 

 one, near the western end of which the city of Saint John is 

 situated. The St. John Group is divided as follows : 



division 1, OR ACADIAN STAGE. 



a. Coarse gray sandstone or quartzite. 



b. Coarse gray sandy shale. 



c. Fine gray and dark gray shales. 



d. Fine dark gray carbonaceous shales. 



division 2, OR JOHANNIAN STAGE. 



a. Coarse gray slates with thin seams of gray sandstone. 



b. Coarse gray slate and gray flagstone, the latter 



predominating. 



c. Gray flagstone and gray slate, in frequent alternations. 



