26 CERTAIN SAND MOUNDS OF 



Seven and one-half feet from the surface in the N. N. E. slope of the mound, 

 with human remains and great numbers of small shell beads, was the perforated 

 vertebra probably of a catfish. The use of the vertebra? of fishes as ornaments was 

 practised in Europe. Dr. Verneau speaks of the vertebrae of a salmon in the caves 

 of Baousse-Rousse, 1 while the vertebral bones of various fishes are described and 

 figured as coming from the same caves by Dr. Riviere, an earlier explorer. 2 



Pearls. — During the course of the excavation a number of globular beads were 

 met with, which examination by means of acid and of the microscope showed to be 

 pearls, the concentric lamination being clearly marked, which would not be the case 

 were the material from the nacreous portion of a shell. 



The subject of pearls in southern mounds has been exhaustively treated by 

 Colonel Jones in Chapter XXI. 3 We learn that not one was found in the stone 

 graves by Dr. Jones, while but few rewarded the search of Colonel Jones. We 

 believe the discovery of pearls in the mounds of Florida to be hitherto unreported. 

 The mounds of Ohio yielded pearls to the investigation of Squier and Davis, while 

 a rich harvest lately rewarded the labors of Mr. Moorehead. The largest specimen 

 from Mt. Royal measured "36 of an inch and "26 of an inch respectively in its major 

 and minor axes. 



Mr. H. A. Pilsbry of the Academy of Natural Sciences of Philadelphia, to 

 whom the beads were submitted, writes as follows : " Having examined again the 

 beads supposed to be pearls, I can state with confidence that true pearls they 

 undoubtedly are. The curvature of the layers in the specimen treated with acid 

 precludes the supposition that they are beads cut from shell, and indicates a pearl 

 of nearly spherical form, four mm. in diameter. Where etched with acid the 

 characteristic structure of concentric laminae of carbonate of lime appears, the 

 layers of animal matter (conchiolin) which alternate with those of lime having been 

 dissolved away. This loss of organic cement leaves the delicate layers of lime 

 unsupported, and the pearls are consequently very fragile. For the same reason 

 the Unios are peculiarly liable to disintegration, contrasting in this respect with 

 the shells of porcellanous structure, such as Ampidlaria and Paludina, found associa- 

 ted with them in the shell-heaps. 



" The pearls were probably, in my opinion, obtained from fresh water mussels 

 (Unio). The only marine shell of the Florida coast which could be expected to 

 produce pearls of this size is Margaritiphora radiata Leach, found abundantly on 

 the Keys, etc. ; but sections of the pearls produced by a closely allied oriental Mar- 

 garitiphora which I have examined have the layers of lime distinctly thinner and 

 closer than in the specimen submitted to me by you. The so-called pearls of Strom- 

 bus or other gastropods need not be considered, as they have an internal structure 

 totally different from genuine pearls. It is therefore likely that your specimens 

 were taken from river-mussels." 



1 L'Anthropologie, Tome troisieme, 1892, page 528. 



2 "De l'Antiquite de l'Homme dans les Alpes-Maritimes," page 273, plate XXI. 



3 Op. at. 



