G8G Systematic Palkontology — Upper Devonian 



Description. — This is a minute pteropod whose sliells, like smooth 

 needle points make spots and patches everywhere through the Genesee of 

 Maryland. Xo other structure except the form of the flattened shells 

 is evident. In the Genesee of New York these shells entirely compose 

 in places a well-marked limestone layer (Styliola limestone) and again 

 in the argillaceous Naples shales above are accumulated in immense 

 numbers wherever calcareous nodules or nodular layers appear. 



Length 3 mm. 



Occurrence. — Jennings Formation, Genesee Member. Present at 

 all the Maryland outcrops of these strata. 



Collection. — ^Maryland Geological Survey. 



Suborder CONULARIDA 

 Family TENTACULITIDAE 



Genus TENTACULITES Schlotheim 



Tentaculites descissus n. sp. 



Plate LXX, Figs. 20-23 



Descripilun. — Elongate Jifiileate cones characterized by diifercntial 

 markings in successive growth stages. The early shell, covering from one- 

 third to one-half the length of the tube, bears subequal and closely ap- 

 pressed annnlations. These rings gradually become more widely sepa- 

 rated and at intervals coarser and broader annuli occur; finally the 

 spaces between the annuli bear only one or two lesser rings and the 

 entire surface shows very iine concentric lines. 



The species is well defined, clearly distinct from the form commonly 

 occurring in the Chemung fauna of New York, T. spiculus Hall. The 

 length of a full-grown s})ecimen is 25 mm. 



Occurrence. — Jennings Formation, Chemung Member. Most com- 

 mon in the vicinity of Deer Park. Garrett County; also in the Polish 

 Mountain section, and Green Eidge, Allegany County. National Eoad 

 west of Frostburg; Oakland-Altamont Eoad; E. Gordon's farm 1 mile 

 northeast of Mountain Lake Park. 



(U)lleclinn. — ^larvbrntl Geological Survev. 



