IOWA ACADEMY OF SCIENCES. 
137 
Silver Lake coal, Beede. (Trans. Kansas Acad. Sci., Yol. XV. p. 30, 
1898 ) One of the upper coal seams of the lower Waubansee (Atchison) 
shales. It is mined in Shawnee county, Kansas, at Silver Lake, and also 
southwest of Topeka. 
Spadra coal, Winslow. (Arkansas Geol. Sur., Ann. Rept. 1888, Vol III, 
p. 32, 1888 ) Near middle of Arkansan series, in Johnson county, Arkansas. 
Spring Creek coal seam, Broadhead. (Missouri Geol. Sur., Rept 1873-4, 
p. 236, 1874 ) Believed to be the same as the Mystic or Mendota coal of 
Putman county, Missouri, adjoining Sullivan county on the north. It lies 
in the Henrietta division. 
Summit coal, McGee. (Trans. St. Louis Acad. Sci., Yol Y, p. 334, 1888.) 
In Macon county, Missouri, the highest seem mined. Upper part of Chero- 
kee. 
Tebo coal, Winslow. (Missouri Geol. Sur , Yol. I, p. 134, 1891.) Appel- 
lation of the chief seam in Henry county, Missouri. Horizon is middle 
Cherokee. 
Thayer coal, Haworth. (Kansas Univ. Quart., Yol. Ill, p. 305, 1895 ) A 
seam in the median part of the Thayer shales, in Neosho coun y, southeast- 
ern Kansas. 
Topeka coal, Haworth. (Kans. Univ. Quart., Yol. Ill, p 278, 1895.) One 
of the seams in the Platte shales, in Shawnee county, Kansas. 
Warrensburg coal, Broadhead. (Missouri Geol. Sur., Iron Ores and Coal 
Fields, pt. ii, p. 184, 1873 ) A thin seam in the upper part of the Cherokee 
division, in Johnson county, Missouri 
Wapello horizon, Bain. (Iowa Geol Sur , Yol. IX, p. 99, 1899.) An 
extensive coal in southeast Iowa, lying in the lower part of the Cherokee. 
Waverly coal, Winslow. (Missouri Geol. Sur., Yol. IX, Sheet Rept. No. 
1, p. 60, 1892 ) In eastern Lafayette county, Missouri, the lowest seam 
mined. Cherokee division. 
Wheeler coal, St. John. (Iowa Geol. Sur., Vol. I, p.276, 1870 ) One of 
the lower coals of the Marais des Cygnes, in Warren county. Iowa. 
What Cheer coal held, Bain. (Iowa Geol. Sur , Yol. IY, p. 284, 1895. 
This coal seam, in Keokuk and Mahaska counties, Iowa, lies very near the 
base of the Cherokee. 
Wier City Pittsburg View, Haworth and Kirk. (Kansas Union Qua t , 
Yol. II, p 105, 1894.) In southeast Kansas, the most important seam of the 
Cherokee. 
VOLCANIC NECKS OF PIATIGORSK, SOUTHERN 
RUSSIA. 
BY CHARLES R. KEYES. 
(Abstract.) 
On the Rostov and Wladikavkas railroad, in southern 
Russia, there rises out of the flat steppes, a few hours be- 
fore reaching the last mentioned place, a remarkable group 
