ILLUSTRATIONS 



PLATE FACING PAGE 



I. Map showing the Distribution of the Devonian Formations of 



Maryland 2:5 



II. North American Paleogeography, Explanation of Symbols 34 



III. Continental Seas of Paleozoic Time 34 



IV. Paleozoic Positive Elements 34 



V. Lower Devonian (New Scotland) 3t) 



VI. Lower Devonian (Becraft) 38 



VII. Lower Devonian (Decewville) 40 



VIII. Middle Devonian (Onondaga) 40 



IX. Middle Devonian (Late Hamilton) 40 



X. Upper Devonian (Ithaca-Chemung) 40 



XI. Fig. 1. — View looking up the Potpmac River from Cacapon Moun- 

 tain, showing Devonian topography 72 



Fig. 2. — View from Prospect Rock on Cacapon Mountain, showing 



Gap in Sideling Hill 72 



XII. Fig. 1. — View showing the Keyser member o*' the Helderberg forma- 

 tion at Keyser, West Virginia 80 



Fig. 2. — View showing the contact of the Keyser member of the 

 Helderberg with the Tonoloway limestone at Keyser, West 

 Virginia 80 



XIII. Fig. 1. — View showing anticline in Keyser limestone near Rawlings 88 

 Fig. 2. — View showing the nearly vertical strata of the Helderberg 



formation at the Devil's Backbone 88 



XIV. Fig. 1. — View showing the anticline of Oriskany sandstone on 



North Branch of the Potomac near junction with South Branch. 96 



Fig. 2. — Detailed view of a portion of Fig. 1 90 



XV. Fig. 1.^ — ^View showing anticline of Oriskany sandstone east of 21st 



Bridge 104 



Fig. 2. — View showing Oriskany sandstone overlain by the Romney 



formation at Monster Rock 104 



XVI. Columnar Sections in pocket at back of volume. 



XVII-XXVI. Ccelenterata-Anthozoa In Atlas 



XXVII-XXX. Coelenterata-Hydrozoa 



XXXI-XXXVI. Echinodermata-Cystoidea 



XXXVII-XL. Echinodermata-Crinoidea 



XLI-LII. Molluscoidea-Brachiopoda " 



LIII-LXXIV. Mollusca-Pelecypoda 



LXXIX-LXXXVII. Mollusca-Gastropoda 



LXXVIII. Mollusca-Cephalopoda 



LXXXIX-XCIV. Arthropoda-Trilobita 



XCV-XCVIII. Arthropoda-Ostracoda 



2 



