MARYLAND GEOLOGICAL SURVEY 89 



Pennsylvania, containing well-preserved trilobites, do not appear to be 

 present in Maryland. 



The few species thus far discovered in the Conococheague limestone of 

 southern Pennsylvania and Maryland give no idea of the characteristics 

 of the Upper Cambrian (Ozarkian) faunas. It is true that the two 

 species of Cryptozoon are. characteristic Ozarkian fossils over a wide area, 

 but very similar species are found in the succeeding Ordovician strata. 

 The single species of trilobite is very limited in its distribution and the 

 brachiopod is too little restricted to be of any stratigraphic value. 



The few Cambrian species identified in Maryland strata are described 

 in the following pages. These species are listed below under their 

 appropriate formations : 



Lower Cambrian (Waucoban) Fossils of Maryland 



Harpers shale. Scolithus linearis Haldemann. 



Antietam sandstone. Scolithus linearis Haldemann, Obolella minor (Walcott), 



Hyolithes communis Billings, and Olenellus thompsoni (Hall). 

 Tomstown limestone. Olenellus thompsoni (Hall) and Salterella sp. 



Middle Cambrian (Acadian) Fossils 



Waynesboro formation. Lingulella sp. 

 Elbrook formation. Dolichometopus sp. 



Upper Cambrian (Ozarkian) Fossils 

 Conococheague Limestone 



Cryptozoon proliferum Hall (common at base) 

 Cryptozoon undulatum n. sp. (common at base) 

 SauJcia stosei Walcott (rare in upper part) 

 Eoorthis desmopleura (Meek) (rare in upper part) 



THE BEEKMANTOWN LIMESTONE 



The middle part of the Appalachian Valley in Maryland, with the 

 exception of the Martinsburg shale belt which is three miles in width, 

 and small areas or other formations, is directly underlain by a thick mass 

 of rather pure limestone. Nearly all of this rock is fine grained and most 

 of it is minutely laminated. Interbedded with these are pure minutely 



