RAYMOND: CORREL.\TIOX OF THE ORDOVICIAN STRATA. 207 



of the war, neither did I see Dalecarha, but Dr. Twenhofel made some 

 collections for me from the district about Rattvik, on Lake Siljan. 

 In Norway, I -visited, under the guidance of Dr. Holtedahl, the 

 Ordovician sections in the vicinity of Christiania and, partly with Dr. 

 Holtedahl and partly with Professor Kiaer, some of the exposures of 

 Stage 4 in the Ringrike district. 



The description of the Palaeozoic strata of Sweden has been very 

 ably summarized in English by Professor Moberg in his Historical- 

 Stratigraphical Review of the Silurian of Sweden and a briefer sum- 

 mary of certain facts in regard to the lower beds of the Ordovician 

 has been published by Fearnsides (59). I am indebted to these two 

 papers, and to the original sources from which their facts were derived, 

 for the greater part of what is here set forth in regard to the geology 

 of Sweden. The greater part of the Ordovician of Norway is still 

 inadequately known. The account here is derived chiefly from the 

 works of Brogger (93-95), and Holtedahl (97). No account in English 

 of this section, except that in Geikie's Geology, has, so far as I know, 

 appeared. 



The strata of Ordovician age in Sweden are found in isolated patches, 

 usually of small area. These patches may be grouped in bands, 

 having a roughly parallel NE-SW alignment. 



The northern band, that in Jemtland and Lapland, has the greatest 

 extent, running far north parallel to the mountains on the boundary 

 between Norway and Sweden. These rocks are, however, except in 

 the southern part, largely metamorphosed. The next band to the 

 south of this has its best exposures in Dalecarlia, and there is a very 

 small area in Gastrikland, especially on the little island of Limon near 

 Gafle. From the evidence of boulders and fossiliferous sand in cracks 

 on the Aland islands, it would appear that this band may once have 

 connected with the Esthonian strata. To the westward the strata 

 of the Christiania district of Norway are in line with these patches. 



The next band is in south-central Sweden, and includes the deposits 

 in Nerike, Ostergotland, and Vasterg5tland, while the fourth band is 

 at the extreme south and includes Scania and Oeland, while the Silu- 

 rian of Gotland is in the same line. The strata are best exposed and 

 least disturbed in Vastergotland and Oeland. A brief description of 

 the strata at some of the principal sections in each region follows. It 

 is rather interesting to note that most of the principal lakes of Sweden 

 are connected with these limestone patches. Thus we find Lake 

 Storsjon in Jemtland, Siljan in Dalecarlia, Hjalmaren in Nerike, and 

 the largest lakes, Vanern and Vattern in connection with the Palaeo- 

 zoic deposits of Vastergotland and Ostergotland. 



