THE CRETACEOUS PERIOD 241 



commonly lignitic. The deposits attain a maximum thickness of 

 about 100 feet. . . . The Matawan consists chiefly of dark-colored 

 clays, in some places micaceous and glauconitic, in its lower part, 

 and of sands, with an interbedded clayey member, locally highly 

 glauconitic, in its upper part. It attains a thickness of about 275 

 feet, although a thickness of 400 feet has been found in deep 

 well borings east of its outcrop. It lies unconformably on the 

 Magothy. . . . The Monmouth group consists of sands and clays, 

 with an interbedded glauconitic division in the northern part of 

 the area. Toward the south the upper sandy formation disappears. 

 The greatest thickness of the group is about 150 feet. The Mon- 

 mouth is conformable to the Matawan. . . . The Rancocas consists 

 largely of greensand marls and sandy calcareous beds which have 

 a maximum thickness in southern New Jersey of about 125 feet. 

 It is conformable to the Monmouth. . . . The Manasquan forma- 

 tion consists of greensand marls and attains a thickness of about 

 50 feet. It is conformable to the Rancocas." x 



Alabama. Lower Cretaceous strata (unnamed) of Alabama, 

 according to Stephenson, consist of " irregular bedded, coarse, 

 arkosic, more or less micaceous sand, with subordinate lenses of 

 usually massive clay of greater or lesser purity. The terrane rests 

 upon a basement of crystalline rocks and is separated from the 

 overlying Eutaw and other Upper Cretaceous and Tertiary forma- 

 tions by an unconformity." 2 



According to Stephenson "the Tuscaloosa formation consists 

 of irregularly bedded sands, clays, and gravels having an estimated 

 total thickness of 1000 feet. . . . The Eutaw formation consists 

 predominantly of more or less glauconitic sand, massive to cross- 

 bedded in structure, with, in parts of the terrane, irregularly 

 interbedded fine laminae and laminated layers of dark clay. . . . 

 The total thickness of the formation is estimated to be from 400 

 to 500 feet. . . . The Selrna chalk consists in the main of more 

 or less argillaceous and sandy limestones rendered chalky by their 

 large content of Foraminiferal remains, with interbedded layers of 

 nearly pure, hard limestone at wide intervals. In western Ala- 

 bama the terrane has a measured thickness of 930 feet. . . . The 

 typical beds of the Ripley formation consist of more or less calcare- 

 ous and glauconitic sands, sandy clays, impure limestones, and 



1 W. B. Clark: U. S. G. S., Professional Paper 71, pp. 609-610. 



2 L. W. Stephenson: U. S. G. S., Professional Paper 81, p. 20. 



