13IHANG TILL K. SV. VET.-AKAD. IIANDL. BAND. 21. AFD. III. N:0 2. 43 



Of the 270 forms (species and varieties) living in Lule 

 Lappmark 34 (including 5 very rare ones) are found in the 

 Ancylus-deposits, or 12,6 %. Of the 250 forms living in Bel- 

 ginm (according to V. H. Syn.) 58 are found in the Ancylus- 

 deposits; or 23, 2 %. Of the 75 forms belonging to the flora 

 of the Ancylus-sea, 34 now live in Lule Lappmark, where 

 five of them are very rare; or 45,3 %, and 58 now live in 

 Belgium; or 77,4 %. Of the 75 forms belonging to the 

 flora of the Ancylus-sea, 27 are common to Lule Lappmark 

 and Belgium Now 34 of the forms I have found in Lule 

 Lappmark belong to the flora of the Ancylus-sea, tlms -^'ai 

 or 80 % of the Anc^^lus-forms living in Lapland are cosmo- 

 politan diatonis occuring in Belgium as well as in Lapland. 



These hgures tend, I think, to show that an examination 

 of the diatomaceous remains found in a deposit may furnish 

 valuable indications of the nature of the climate which pre- 

 \ailed during the formation of that deposit. 



The diatomaceous flora of Lule Lappmark proves to be 

 relatively very rich, no less than 270 forms being already 

 found. As it is of a decidedly boreal character, I have com- 

 pared it with the diatomaceous freshwater flora of Spetsbergen 

 and liussian Lapland, described in Lagerstedt, :Sötvattens- 

 diatomacéer från Spetsbergen och Beeren Eiland.-, and P. T. 

 (!leve, »The diatoms of Finland.. It may be observed 

 then, that of about 100 species and varieties, stated by 

 Lagerstedt, 1. c. as occuring in Spetsbergen and Beeren 

 Eiland, only 50 % have been found in Lule Lappmark. On 

 the other hand 55 species found by me in Lule Lappmark, 

 are not mentioned by P. T. Cleve, 1. c, as now living in 

 Russian Lapland, which thus either has a scantier flora in 

 this regard, or is in want of being further investigated. 



In order to compare the recent flora with the past, I 

 have studied 2 samples of subfossil diatom-earths from peat- 

 bogs in Lule Lappmark, the one from Muddas Ape, the other 

 from Ripas near Gellivara. Both these gatherings have been 

 issued in Cleve and Möller, Diatoms, I, 37 and V, 270, 271 

 where Grunow gives a list of some of the forms which they 

 contain. As might be supposed, this list shows a great re- 

 semblance with the recent flora of the country in question. 

 All the forms found in the sample from Muddas Ape live at 

 precent in Lule Lappmark in some abundance, for instance: 



