Dr. HoM—Thc Glacial Period and Oscillation of Land. 205 



V. — The Connection of the Glacial Pekiod with Oscillation 

 OF the Land, especially in Scandinavia. 



By Dr. Nils Olof Holst. Translated by F. A. Bather, D.Sc. 



[In a recently published paper ' Dr. N. 0. Hoist, of the Geological 

 Survey of Sweden, has given a detailed description of the Post- 

 Glacial deposits of the Baltic Sea and the Gulf of Bothnia. The 

 paper is accompanied by a map showing the chief points of observation. 

 The determination of the different horizons depends on (1) the 

 stratigraphy; (2) the sub-fossil diatomaceous flora; (3) the sub- 

 fossil higher flora. The stratigraphical evidence is in the form 

 of numerous sections, taken all along the coast. The diatoms are 

 used chiefly, but not solely, to distinguish the marine from the 

 fresh-water deposits ; their determinations, nearly 3,000 in number, 

 are due to Professor P. T. Cleve and his daughtei", Dr. Astrid Cleve. 

 The remains of the higher plants have been determined by 

 Dr. Gunnar Andersson. 



The fresh-water [Ancijlus) epoch and the salt-water (IJtorina) 

 epoch are divided by the author as follows : — 



1. The oldest Ancylus epoch, the deposits of which age in 

 southern Sweden partly are barren, partly contain Arctic plants. 



2. The middle Ancylus epoch, of which the deposits contain 

 the remains of fir and birch. During this epoch the land-ice melted 

 away from the lower parts of central Sweden, and the sea came 

 into the Baltic, making the water temporarily salt. 



3. The youngest Ancylus epoch, or the older half of the oak 

 epoch. 



4. The Litorina epoch, or the younger half of the oak epoch, 

 when the present communication with the sea was opened, and the 

 water of the inland sea, which during the Ancylus epochs had been 

 fresh as a rule, now became salt. 



The fact that the climate became temporarily colder in the middle 

 of the Litorina epoch is established b}' finds of boreal diatoms : 

 Navicula semen, N. amphibola, Pinnularia streptonqjhe, etc. 



Wider interest attaches to the concluding pages (113 et sqq.), in 

 which the author deals with the question of oscillation of the land 

 in Scandinavia and with the explanation of the Glacial Period, on 

 which matters he expresses some new views. We therefore ofter 

 a full translation of this part of Dr. Hoist's memoir.] 



I HAVE elsewhere - shown that the events immediately connected 

 with the melting of the Scandinavian land-ice occuri'ed in rapid 

 succession. The same was the case with the oldest Post-Glacial 

 events. Thus it has been demonstrated in the present paper that 

 the Glacial marine clay and sand, deposited along the present coast 



1 "Bidrag till kiiunedomeu om Ostersjcins ocli Bottuiska Vikens postglaciala 

 geologi": Sveriges Geoloo-iska Uiulersokning, Alliaudl., scr. C, No. 180. 8vi>; 

 128 pp., 1 map; 1899 (published March, 1901). 



* N. 0. Hoist, "liar det funnits mer iin en istid i Sverige?": Sver. Geol. 

 ITnders., 1895, ser. C, No. 151, see pp. 36-39. German translation by W. Wolff, 

 " Hat es in Schwedeu mehr als eine Eiszeit gegeben r" pp. 38-42 ; Berlin, 1899. 



