Maeyland Geological Survey 161 



Helderbeeg Formation 

 Keyser Member 



Horizontal Vertical Total 



Road N. 30° W. distance thickness vertical 



feet feet thickness 

 Nodular limestone, partially concealed, containing 



Cladopora rectilineata 229.0 12.0 75.0 



Concealed 193.0 l.G 63.2 



Nodular limestone, partially concealed above, con- 

 taining Cladopora rectilineata 188.0 8.0 61. G 



Concealed 165.0 8.0 53.6 



Road N. 45° W. 



Nodular limestone 142.0 .G 45.6 



Concealed 140.0 4.0 45.0 



Very nodular limestone 127.0 3.0 41.0 



Concealed. Nodular limestone in part 117.0 15.0 38.0 



Nodular limestone partially concealed 71.0 2.0 23.0 



Disintegrating nodular limestone 64.0 10.0 21.0 



Largely concealed. Thin-bedded nodular limestone 



containing Camarotwchia litchfleldensis, Chonetes jer- 



seyensis, Rhynchospira globosa, Spirifer cf. vanuxemi 



var 34.0 5.0 11.0 



Thin-bedded nodular limestone containing at base 



Favosites favosus var. integritabulatus (a), F. pyri- 



forniis (Si) 19.0 G.O 6.0 



Thickness of Keyser member exposed 75.0 



ToNOLowAY Formation 



Concealed 3.0 1.0 



Fissile limestone, largely concealed with heavier 

 beds 25 to 27 feet, 39 feet, and 61 feet below Helderberg- 

 Tonoloway contact. 



Hancock Area 

 XVI. Section at Tonoloway 

 The Potomac Eiver cuts through Tonoloway Eidge at Tonoloway 

 Station on the Western Maryland Eailroad, opposite Great Cacapon, West 

 Virginia, where the finest section of the Lower Devonian east of Cumber- 

 land is exposed. The section is seen in the cut of the Western Maryland 

 Eailroad just east of the station/ 



^The llthological description of the section is by Ulrich and Stose; Pawpaw- 

 Hancock Folio, U. S. Geol. Survey, 1912; the faunal, by C. K. Swartz except 

 the lower 60 feet which is by T. P. Maynard and C. K; Swartz. The figures 

 given after names of fossils Indicate altitude in feet at which the fossils were 

 found above base of section. 

 11 



