2 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I43 



man, Jr., of the National Aeronautics and Space Administration, and 

 E. P. Henderson, of the Smithsonian Institution, have generously- 

 shared their knowledge of tektite specimens and literature with the 

 senior author in many helpful discussions. 



PREVIOUS WORK 



The initial identification of tektites from Georgia was made by E. P. 

 Henderson of the Smithsonian Institution's Division of Mineralogy 

 and Petrology. Two specimens (USNM 1396) were submitted for 

 examination and an identification was made during 1938. Confirma- 

 tion of Georgia as an area of tektite occurrence has been reported 

 by Barnes and Bruce (1959). Bruce (1959) has published a general 

 discussion of tektite finds in Georgia, and included in his paper are 

 photographs of several specimens. Cohen (1959) has discussed 

 Georgia tektites with particular reference to their similarity to 

 moldavites and bediasites. His paper includes a compilation of physi- 

 cal properties and spectrochemical data. Senftle and Thorpe (1959) 

 have measured the magnetic susceptibility and intensity of mag- 

 netization for the Georgia tektite and for a number of other tek- 

 tites, and have discussed the significance of these measurements. 

 Reynolds (i960) and Gentner and Zahringer (i960) have meas- 

 ured potassium-argon ages for the major tektite groups. These data 

 show that Georgia tektites and bediasites are of similar age, but 

 that moldavites are much younger. Stair (1955a, 1955b, 1956) has 

 published the absorption spectra and a photomicrograph of this same 

 Georgia specimen. He also gives a photograph of a second Empire, 

 Ga., tektite. The measurements reported in the literature on Georgia 

 tektites by all the workers cited above have been made on portions of 

 one specimen, USNM 1396. 



The only previous experimental work using material from the 

 Martha's Vineyard tektite other than a chemical analysis reported by 

 Kaye et al. (1961) is that of Pinson and Schnetzler (i960). These 

 authors have determined rubidium and strontium contents and stron- 

 tium isotope ratios. 



MORPHOLOGY AND INTERNAL STRUCTURE 



The two tektite specimens with which we are particularly concerned 

 have both similarities and striking differences in gross morphology. 

 Plate 1 is a direct-light photograph of (A) the Empire, Ga., and (B) 

 the Martha's Vineyard, Mass., tektites. Plates 2 and 3 are photo- 

 graphs of these specimens after ammonium chloride smoking to bring 



