THE MOLDAVITES 281 



trial origin, it is of interest to examine the strain phenomena in speci- 

 mens of moi(Ui\ites. Moldavites are fragments of a green-eolorcd glass 

 which occur in certain gravels in Bohemia, especially near Budweiser and 

 Treibitschj and are characterized by remarkable surface markings similar 

 to those described above. The distribution of the moldavites is not 

 unlike that of Indian arrow-heads in the Middle West. The moldavites 

 occur here and there, but never in any manner indicative of their origin. 

 They approximate in composition a rhyolite glass high in silica. Because 

 of their abnormal distribution and remarkable surface markings, Suess 

 concludes, following a suggestion of E. D. M. Verbeek/^ that they are 

 meteoritic in origin, derived possibly from the moon. H. S. Summers,^'' 

 in a recent study of obsidianites, concludes that the chemical evidence 

 also indicates that they are of meteoritic rather than of volcanic origin. 

 G. P. Merrill/® on the other hand, presents evidence against the necessity 

 for considering the moldavites to be of extraterrestrial origin because of 

 their external surface markings. The present study tends to confirm 

 and to strengthen the objections advanced by Men-ill. 



With a proper choice of solution and temperature, it should be rela- 

 tiveh^ easy on rapidly chilled specimens of glass of moldavite composi- 

 tion to reproduce the surface markings and thus to produce artificial 

 moldavites. This Professor Merrill has shoA^oi to be possible by simple 

 means, namely, by suspending fragments of obsidian or glass in hydro- 

 fluoric acid vapor. The mode of occurrence of the Hrafntinnuhryggur 

 fragments is a good example of the result of the process at work in nature 

 on a large scale. 



Two instances may be cited to prove that etching phenomena of this 

 type can bo produced on other materials: (a) In the course of experi- 

 ments on the etching of cleavage fragments of calcite, the writer ob- 

 served etch pits and channels in process of formation on the under side 

 of the fragment immersed in a weak solution of hydrochloric acid in a 

 beaker.^" (h) On a specimen of stalactite from Luray, Virginia (U. S. 

 ISTational Museum specimen 88436), the surface is pitted and grooved 

 with shallow markings across the concentric layers not unlike some of the 

 markings on the moldavites. 



Passing now. to the consideration of strain phenomena exhibited by 

 the moldavites. we may first direct our attention to the different effects 

 which result from the various physical conditions under which strain is 



1" .Tahrboek van het Arijiiwrscii in hcilci-l.-iiidish Oosliiulir. \(.l. x.\. IS'.iT. p. I'.'l.". Am- 

 sterdam. 



'■ Proc. Roy. Soc. Vicdnia. vol. ill. |,(. 2. 1!»on. p. 4li.S. 

 I*' Proc. U. S. National Museum, vol. 40. r.ill. p. 4S.-.. 

 '" Neues THhrliucli. I'.oilaRo Rd. xviii. 10(14. p. .'',40. 



XXr — Bi'i,L. (Jkul. Soc. Am., Vot.. 26, 1014 



