94 On a deposit of Fossil Diatomacese in Aberdeenshire. 



of DiatomacecB. Being desirous of procuring additional infor- 

 mation respecting the probable circumstances under which such 

 a deposit might have taken place, I requested some particulars 

 respecting it; my disappointment was considerable when informed 

 that the decomposed felspar alone had been found under a bed 

 of clay, but that the white powder was in reality the residue left 

 after the use of peat as fuel, a quantity of which had been pre- 

 served, its peculiar appearance having attracted notice. The 

 fact, however, is not less interesting when viewed in connection 

 with a true fossil earth to be presently described, which was 

 found by Mr. Murray, at Blackhouse near Peterhead, under a 

 bed of peat, for specimens of which I am indebted to my friend 

 Professor MacGillivray. The residue of the Premnay peat was 

 found to consist of the following Diatomacece : — 



Eunotiece *. Cocconema lanceolatum. 



Eunotia ocellata. Gomphonema lanceolatum ? 



E. tetraodon. 'Naviculea. 



E. turgida. 



Himantidium Areas. fNavicula acrosphcEna. 



N. binodis. 



MeridiecE. n. dicephala. 



Meridion circulare. -{-N. major. 



Frag'ilariece. N. nodosa ^. striata. 



Fragilaria rhabdosoma. JN. viridis 



btauroneis lanceolata. 

 Meloseirece. S. linearis. 



fMeloseira Italica. S. Microstauron. 



„ . „ fS. Phoenicenteron. 



ourireuece. 



fSm-irella bifrons. ^ ^ TahellarietB, 



Synedra Ulna. Tabellaria ventricosa. 



CymbellefB. CoscinodiscecB. 



Cymbella Elirenbergii. Coscinodiscus minor. 



This last was detected by Mr. Thwaites, to whose assistance I 

 am indebted in naming the species. Those marked f were in 

 greatest quantity, and the Meloseira Italica was more abundant 

 than the others ; this species had not, so far as I am aware, been 

 hitherto included in the list of British species, and I have found 

 it in a living state very abundantly in several localities near Aber- 

 deen ; it generally occurs at the sources of cold springs. 



The residue so rich in Diatomacece, remaining after burning 

 peat from the Premnay bogs, renders it exceedingly probable 

 that separate deposits of fossil Diatomacece may yet be detected 

 there. 



The specimen from Peterhead, in possession of Dr. MacGil- 

 livray, is a mass of small specific gravity having a laminated 



* The names are adopted from Kutzing's work on the Diatotnacets.. 



