BV T. W. EDGEWORTH DAVID. 267 



minerals by the discharge of steam and various gases from 

 apertures in the several basins into which it finds its way. . . . 

 The small cool spring above referred to contains abundance of 

 JVavicu/ce and other Diatoms, such as those met with amongst the 

 green matter growing in very hot water." He also obser^'es (op. 

 cit. p. 323), " In this water, which was too hot to bear the finger, 

 the same Chroococcus as observed at the springs near the lake was 

 abundant," etc. . . . ''A little lower down in a small pool of 

 hot mud and water, so hot that the finger could only be borne in 

 it for a short time, grows a sedge . . . and an abundant 

 growth of alga^, Chroococcus, Oscillatoriie \^7hIi/jjhothri.r f. Archer. 

 T.W.E.D ] and some Diatoms with endochrome complete." 



The temperature of the springs in the lake of Furnas is quoted 

 (op. cit. p. 324), f. Hartung* as from 78' to 190° Fahr. The 

 water in which the Chroococcus grew is estimated to have had a 

 temperature of 149° to 158° Fahr., and that in which the sedges 

 grew of 113° to 122° Fahr. Mr. W. T. Thiselton Dyer, in notes 

 on Mr. Moseley's collections (op. cu. p. 326), states that in the 

 collection submitted to him "from among the sedges at Furnas in 

 very hot water " he identified a number of Diatoms, which he 

 specifically names. He adds that they were not numerously 

 represented, however, and says (p. 327), " These are all forms of 

 common occurrence, and seemed in no way affected by the high 

 temperatui'e of the water." A useful bibliography of references 

 to the vegetation of hot waters is contained in Ninth Report, 

 Geol. Sur. U.S.A. 1887-88, pp. 620-628. It is noted (op. ell. 

 p. 625, quoted from Manual of Geology, by .James D. Dana, 

 3rd ed., 1880, p. 611) that "Mr. James Blake found diatoms in 

 water having a temperature of 163° F. at Pueblo Hot Springs, 

 Nevada." It is also stated (ibidem), " At the Mammoth Hot 

 Springs, Dr. F. V. Hayden observed the occurrence of pale yellow 

 filaments about the spi^ings and the green confervoid vegetation 

 of the waters, as well as the presence of diatoms in the basins of 

 the main springs, two species of the latter, Palmella and Oscillaria, 



"Die Azoren," Leipzig, W. Englemann, 1860, p. 173. 



