BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 

 Vol. 25, pp. 745-780, PLS. 26-28 DECEMBER 16, 1914 



ORIGIN OF OOLITES AND THE OOLITIC TEXTURE IN 



ROCKS 1 



BY THOMAS CLACHAR BROWN" ^ 



{Presented before the Society December SI, 1913) 



CONTENTS 



Page 



Introduction and historical sketch 745 



Historical review : 747 



Oolites from Great Salt Lake, Utah. 752 



Calcareous oolites from Cambrian and Ordovician beds of Pennsylvania. . 757 



Siliceous oolites of Pennsylvania 760 



Bellefonte type of siliceous oolites 764 



Clinton oolitic iron ore 768 



Summary and conclusions 773 



Bibliography 774 



Explanation of plates 778 



Introduction and historical Sketch 



The study of oolites and oolitic texture has no claim to novelty. This 

 peculiar texture early attracted the attention of scientists, and the micro- 

 scope was used to elucidate the minute structure of these rocks nearly 

 two centuries before the petrographic microscope came to be recognized 

 as a necessary adjunct of a petrographic laboratory. As early as 1664 

 Hooke described in his volume on "Micrography'^ ^ an oolite under the 

 name of "Kettering-stone." His description runs thus : 



"This stone which is brought from Kettering in Northamptonshire, and 

 digg'd out of a quarry, as 1 am inform' d, has a grain altogether admirable, 

 nor have I ever seen or heard of any other stone that has the like. It is made 

 up of an innumerable company of small bodies, not all of the same cize or 

 shape, but for the most part, not much differing from a globular form, nor 

 exceed they one another in diameter above three or four times; they appear 



^ Manuscript received by the Secretary of the Society December 31, 1913. 



2 Introduced by Florence Bascom. 



' Robert Hooke : Micrography, or some physiological descriptions of minute bodies 

 made by magnifying glasses, with observations and Inquiries thereupon. November 23, 

 1664. 1667. 



LIV — Bull. Gbol. Soc. Am., Vol. 25, 1913 (745) 



