1874.] 127 [Johnston. 



of the celebrated " Bermuda Tripoli," so rich in peculiar forms of 

 DiatomaceEe, described by Ehrenberg and the late Prof. J. W. Bailey. 

 " F. K." says that " Mr. Geo. Norman of Hull, England, found that it 

 came from Nottingham, Maryland." 



As the Nottingham earth came from our corresponding member, 

 Prof. Christopher Johnston of Baltimore — and that it was possible 

 that Nottingham was the original locality, was well known in this 

 country'independent of Mr. Norman — I applied to Prof. Johnston 

 for the authentic history of that deposit; to which he replied by the 

 paper herewith appended. Mr. Norman's paper is in the " Quarterly 

 Journal of Microscopical Science," January, 1861. In that paper he 

 does not say that the Bermuda came from Nottingham, as " F. K. " 

 represents, but only suggests the possibility of the case, as American 

 diatomists had before him. Since Dr. Johnston's paper was written, 

 Dr. Josiah Curtis has visited that part of Maryland, and discovered 

 numerous other localities of the diatomaceous earth, containing the 

 same forms as the Bermuda and Nottingham deposits. 



About the Rediscovery of the " Bermuda Tripoli," near 

 Nottingham, on the Patuxent, Prince George's County, 

 Maryland. By Christopher Johnston, M.D. 



In 1854 I had the great pleasure of being a correspondent of Prof. 

 J. W. Bailey of West Point, and during the year received from that 

 distinguished gentleman valuable guidance, and also specimens of 

 diatomaceous material, among others a very small portion of a buff- 

 colored dust, labelled " Bermuda Tripoli." From this I prepared a 

 single slide, now in my possession, containing very beautiful forms, 

 chiefly Heliopelta, Corcinodiscus, Craspedodiscus, Aulacodiscus Crux, 

 and Eupodlscus Rodgersii. 



At a later period I was in correspondence with my friend J. Sulli- 

 vant, Esq., of Columbus, and while making some exchanges, I asked 

 for "a good boiling of Bermuda Tripoli" ; to which request Mr. S. 

 replied, June, 1859, "I would send you a quantity if I had it. I 

 have nothing but a slide, and I have been long struck with its resem- 

 blance to the Richmond earth In a letter just received from 



Mr. Geo. Norman, he says ' what a pity the locality of Bermuda 

 Tripoli and its beautiful fossils has been lost;' and then adds 'that 

 himself and Dr. Arnott had come to the separate and independent 

 conclusion that they never came from Bermuda at all, but from Ber- 

 muda or James River in Virginia.' I have very little doubt of it, 



