250 VAUGHAN AND COOKE: HAWTHORN FORMATION 



GEOLOGY. — Correlation of the Hawthorn formation.'^ Thomas 

 Wayland Vaughan and Charles Wythe Cooke, Geologi- 

 cal Survey. 



Dr. W. H. Dall in 1892 applied the name Hawthorn beds to 

 certain upper Oligocene deposits of clay and phosphatic sand- 

 stones which outcrop in northern Florida and are characterized 

 by silicified oyster shells and silicified corals. Among the locali- 

 ties mentioned are several near Hawthorn, Devils Mill Hopper 

 near Gainesville, the hilltops near Archer and Arredonda, Nigger 

 Sink and a well near Newnansville, Fort White, a sink 4 miles 

 north of Lake City, and White Springs on Suwannee River'. 

 In 1894. Doctor Dall published the statement that the Hawthorn 

 beds are to be correlated with the Chattahoochee series, as are 

 also the Orthaulax bed and Tampa limestone at Tampa and the 

 chert of Hillsboro River. This correlation was adopted by Clapp 

 and Matson. 



Studies subsequent to those of Doctor Dall, published in 1894, 

 have all tended to confirm the essential correctness of his opinion 

 regarding the age relations of the Chattahoochee "series" and 

 the beds around Tampa mentioned by him; but additional 

 information obtained during the progress of field work in Florida 

 having led to doubts as to the correctness of the stratigraphic 

 reference of the Hawthorn beds, a special re-examination of all 

 important localities was made during the field season of 1913. 

 In this connection, in fairness to Doctor Dall, it should be stated 

 that his account of the Hawthorn "beds" was mostly based on 

 the field notes of others and that he did not personally examine 

 the critical exposures. An exposure at White Springs, Suwannee 

 River, Hamilton County, proved to be the key to the problem. 

 Following is the description of the section at this locality pub- 

 lished by Doctor Dall from notes supplied by Dr. J. C. O'Neal: 



At White Springs on the Suwannee the following section was ob- 

 tained : 



1 Published by permission of the Director of the U. S. Geological Survey. 



