M\RYI,AN1) Oi:OI,OGK'AL SfltYRY 249 



riior/ililiKi pnililriini. 'I'lic (lcsciij)tion of this form precedes P. gihha l)y 

 nearly ')U years nml if any change is made tliis must be given the prefer- 

 ence and P. gibba be luade a variety of Polymorphina lacica. Inasmuch 

 as there is Just as great danger of placing together many forms with 

 vaiictal (lisliiictioiis as lliere is in making too many species it is not at- 

 triii|it('(l at the present time (o change previous determinations and 

 spceilic names. While found in almost every sea it is more abundant in 

 the shallow waters of temperate latitudes. It was not dredged by the 

 ChalK'ugor in the jSTorth Atlantic at a groatci' ilcpth tliaii HiO fathoms 

 but iu the South Atlantic was found at 1990 fathoms, North Pacific at 

 2300 fathoms, South Pacific, 2350; but in all these cases the specimens 

 are rare and of exceedingly small size, showing that they belong to shal- 

 low water temperate zoncal forms. Its geological range is likewise wide 

 and has been repeatedly recorded from tlio Jura, Cretaceous, and the 

 various Tertiary deposits. It has been found in the "^^iof•on(' of Plum 

 Point, where it is rare. 



Occurrence. — Aquia Formation. Upper Marlboro. 



Collection}. — Maryland Geological Survey. 



Polymorphina praelonga Terquem. 

 Plate LXIII, Fig. 14. 



Polymorphina praelonga Terquem, 1878, Mem. Soc. ffeol. France, series 3, [ivol. i, 



p. 39, pis. iii, viii, tigs. 20, 31. 

 Polymorphina praelonga Bagg, 1896, Bull. 141, U. S. Geol. Survey, p. 92. 

 Polymorphina praelonga Bagg, 1898, Bull. Amer. Pal., No. 10, p. 31. 



Description. — Test elongate oval, attenuated anteriorly; smooth and 

 glistening; nearly circular in transverse section; three or four slightly 

 raised, elongate chambers marked by somewhat depressed septa. Length, 

 0.79 mm. 



This species, with its many varieties of form, is beautifully illus- 

 trated in Terquem's Monograph on the Eocene Foraminifera about 

 Paris. 



It is said to be more abundant in the Eocene but quite rare in de- 

 posits of (later) Pliocene age. 



Occurrence. — Nanjemoy Formation. \Voodstock. 



Collection. — Johns Hopkins University. 



