1-98 proceedings: geological society 



The geologic range of bentonite and the areas within which it is known 

 to exist show that volcanic products probably make up a larger part of 

 the Cretaceous sediments of the region than has been recognized here- 

 tofore. Beds of bentonite are present in the Bighorn Basin section, 

 3000 feet below the horizon equivalent to the base of the Livingstone 

 formation in Montana, which is largely made up of volcanic materials. 

 The source of these volcanic products cannot be determined, but prob- 

 ably is to be found in the region west of eastern Idaho and Utah. 



Discussion: C. J. Hares spoke of the distribution and geologic re- 

 lationships of bentonite. E. T. Wherry outlined a process by which 

 bentonite is made into a commercially important product for the soft- 

 ening of water. The bentonite is heated and treated with an alkali 

 salt. The resulting material will exchange its alkali for the lime of 

 hard water. F. J. Katz called attention to the unusual process of al- 

 teration involved in the explanation of the origin of bentonite as pre- 

 sented. 



Frank J. Katz : Stratigraphy in southwest Maine and southeast New 

 Hampshire. The following sedimentary formations and groups have 

 been established for the coastal region between the head of Casco Bay, 

 Maine, and southern New Hampshire : 



The Berwick gneiss, consisting of highly metamorphosed and re- 

 crystallized graywacke, quartzite, and thin micaceous beds, which are 

 developed in a belt 1 to 10 or more miles wide extending southwest from 

 Falmouth and Gorham, Maine, to and beyond Lee, New Hampshire. 

 The formation is of undetermined but probably pre-Cambrian age. 



An Algonkian (?) crystalline complex of quartzite, rhyolite, horn- 

 blende schist, and graywacke gneisses in Kittery, Maine, and Ports- 

 mouth, Newcastle, Rye, and North Hampton, New Hampshire. 



The Carboniferous (Pennsylvanian?) Kittery quartzite, a thick for- 

 mation containing thin-bedded quartzites and argillites in a belt about 

 10 miles wide along the coast from Saco, Maine, to Portsmouth, New 

 Hampshire, and continuing thence inland in a southwesterly direction 

 to the Merrimack River, where it forms part of the Merrimack quartzite 

 of Massachusetts. 



The Eliot slate, the rocks of the Casco Bay group, and the rocks of the 

 Rochester, New Hampshire basin, which are developed in three separate 

 areas but are approximately equivalent and conformably above the 

 Kittery quartzite. Of these the Eliot slate, in Eliot, Maine, and Dover, 

 New Hampshire, and extending thence southwest in two belts, consists 

 of gray sericitic and silicious slates, argillo-quartzitic schists, calcareous 

 beds, and carbonaceous phjdlites. The Casco Bay group occupying 

 an area about 12 miles wide and 30 miles long extending along the 

 coast from Saco, Maine, to the head of Casco Bay, consists of the Cape 

 Elizabeth formation of graywacke schists, gray gritty slates, sericite 

 phyllites, and calcareous carbonaceous laminae; the Spring Point green- 

 stone; the Diamond Island slate, a graphitic and pyritiferous quartz 

 slate; the Scarboro phyllite, a carbonaceous sericite phyllite; the Spur- 

 wink limestone; the Jewell phyllite; and the Mackworth slate. The 



