MARYLAND GEOLOGICAL SURVEY 103 



The Maryland outcrops of the Cryptozoon steeli zone are so numerous 

 and easily located both on the map and in the field that only a few locali- 

 ties need be mentioned. In the western half of the valley, outcrops along 

 the Western Maryland Railway, especially three-quarters of a mile east 

 of Charlton, show these rocks and their contained fossils. East of the 

 Martinsburg shale belt, exposures in the vicinity of Williamsport and 

 also north and west of Hagerstown have afforded fossils. In the western 

 part of the valley the line of hills in the Beekmantown area next to the 

 Beekmantown-Conococheague boundary represents this zone, but in the 

 eastern part the exposures parallel a line of hills caused by the more 

 resistant Stonehenge beds. 



Ceratopea Zone. Succeeding the dove and pink pure limestones and 

 marbles of the Cryptozoon steeli zone are 250 feet of blue and dove lime- 

 stone cherty in the upper half, containing horn-like fossils known by the 

 generic name Ceratopea. The exact nature of these fossils is unknown, 

 but they are believed to be the opercula of large gastropods like Maclu- 

 rites. From a stratigraphic standpoint they are of considerable interest 

 because this particular species and the fauna associated with it has a wide 

 geographic distribution, but restricted geologic range throughout the 

 Appalachian and Mississippi valleys. Free silicified specimens of this 

 organism occur in the soil where this zone outcrops, or they may be found 

 attached to the limestone. Associated with the Ceratopea are a few 

 species of gastropods and fragments of trilobites, but the Ceratopea itself 

 is the most characteristic fossil of the division. In Maryland numerous 

 outcrops of this zone can be found in the vicinity of Halfway, particularly 

 in cuts along the Cumberland Valley Railroad. Localities near Hagers- 

 town have also afforded this fossil, although in no place has it been found 

 in the abundance that prevails in Virginia and the states to the south. 



The fauna of the Ceratopea zone so far identified consists of nine 

 species. Fragments of a few other species have been noted, but they are 

 too imperfect for description and can only be identified with certainty 

 when a monographic study of the entire Beekmantown formation has 

 been made. 



