TWENHOFEL: EXPEDITION TO THE BALTIC PROVINCES. 303 
5. Lyellia bacillifera. 
6. Proheliolites dubius. 
7. Atrypa imbricata. 
8. Clitambonites sinuatus. 
9 verneuili. 
10. Dalmanella wimani. 
11. Orthis oswaldi. 
12. Platystrophia biforata lynx. 
13. Strophomena assmussi. 
14, semipartita. 
15. Chasmops eichwaldi. 
16. Isotelus robustus. 
17. Proetus ramisulcatus. 
Dr. Bassler from his faunal studies of Baltic Russian strata stated 
that it appeared very probable that a great time break exists within 
the Lyckholm formation, and “that the Wesenburg and early Lyck- 
holm show affinities with the early Trenton, and that the upper 
Lyckholm and Borkholm closely resemble certain divisions of the Rich- 
mond group.”! He describes the Lower Lyckholm as a “ Magnesian 
limestone holding Maclurea, Subulites and other gastropods related 
to American Trenton species” ? and “The bryozoans of the lower 
Lyckholm are, like those of the American Galena, distinctly Trenton 
in character.” In his table of correlation he places the Lower Lyck- 
holm as the equivalent of the Stewartsville dolomite of the Mississippi 
Valley.2 In drawing his conclusions Bassler labored under the 
extreme difficulty of never having seen the strata in the field and he 
also had to accept the statements on the labels attached to the speci- 
mens which he studied. . 
Born‘ dissents from the conclusion of Bassler relating to a time 
break in the Lyckholm and denies its existence. He also disagrees 
with Bassler on the correlation of the Lyckholm; but as he fails to 
definitely state its stratigraphic equivalent in the American section, 
referring it to two possible horizons, this objection need not be further 
considered. Schmidt® described the Lower Lyckholm as a white, 
thick-bedded limestone, rich in silica and carrying few corals; while 
1 Bassler. Bull. 77, U.S. N. M., 1911. 
2 Bassler. Loc. cit., p. 9. 
3 Bassler. Loc. cit., p. 17, 38. 
4Born. 1913, Centralbl. min., geol., pal., 1913, no. 22, p. 714-19. 
* Schmidt. Mem. Acad. sci. St. Petersb., 1881, ser. 7, 30, no. 1, p. 37. 
