124 Rev. W. Smith on Deposits of Diatomaceous Earth. 



as an acute observer in another dejDartment of natural history is 

 not unknown to the readers of the ' Annals '), is a large and hand- 

 some species intermediate between E, zebra and E. granulata^ 

 but distinguished from both by its stouter habit, the regular 

 convexity of its dorsal outline, and its rounded ends. I add a 

 description in a note*. 



fEpithemia Musculus. 



t zebra. 



t ocellata. 



t gibba. 



\ turgida. 



granulata. 



Hyndmanii. 



fHimantidium pectinale. 



Fragilaria virescens. 



capucina. 



tCj'clotella operculata. 



minutula, 



fMelosira orichalcea. 

 \ arenaria. 



Campylodiscus noricus. 



Surirella splendida. 



t bifrons. 



f Solea. 



t elliptica. 



fSynedra capitata. 



t biceps iS. recta. 



\ ulna. 



sigmoidea. 



tCocconeis Pediculus. 

 fCymbella Ehrenbergii. 



cuspidata. 



tCocconema lanceolata. 

 f cymbiformis. 



fCocconema Cistula. 

 fGomphonema acuminatum. 

 t constrictum. 



geminatum. 



f Navicula nobilis. 



•f major. 



\ viridis. 



t sphaerophora. 



t radiosa. 



nodosa jS. striata. 



binodis. 



lata. 



dicephala. 



mesolepta. 



't' elliptica. 



firma. 



t attenuata. 



•f Stam-oneis Phoenicentron. 



punctata. 



lanceolata. 



cardinalis. 



"^ lineolata. 



amphicephala. 



Platystoma. 



t Amphora ovalis. 



Tabellaria fenestrata. 



ventricosa. 



It is evident from the above that neither of the deposits found 

 can with strictness be termed fossil ; that they are simply the 

 siliceous coverings of species, the greater number, if not all, of 

 which, still inhabit the waters of the lake, having required no 

 doubt a lengthened period for their accumulation, but still one 

 comparatively recent, and which cannot be regarded as conferring 

 a fossihferous character on the deposit itself. 



In the ' Magazine of Nat. Hist.' for July 1839, an interesting 

 description of an " Infusorial " earth found on draining Lough 

 Island- Reavey, co. Down — is given by Dr. Drummond of Bel- 

 fast : I have been enabled by the kindness of W. Thompson, Esq. 

 of that town to compare this deposit with those I have here 

 noticed. Although occurring under very similar circumstances, 



* Epithemia Hyndmanii, W. Sm. E. major, a latere secundario valde 

 et acqualiter convexa, apicibus obtusissimis rotundatis non recurvatis, striis 

 transversalibus moniliformibus vix convergcntibus : a latere primai'io ob- 

 longa medio valde dilatata. Long. Tri^-T^^ uncisc. 



