PORTAGE AND CHEMUNG FORMATIONS OF MARYLAND 331 



Schizophoria striatula (Schloth) was found, a species abundant in the 

 Ithaca of New York, and at 785 feet Spirifer pennatus var. posterus 

 Hall and Clarke, was observed. 



At an altitude of 1,000 feet a profusion of individuals was found 

 belonging to the following species: 



Spirifer pennatus var. posterus Hall and Clarke, abundant 

 Productella speciosa Hall, abundant 

 Leiorhynchus globuliforme (Vanuxem), common 

 Pugnax pugnus (Martin), common 

 Cyrtina hamiltonensis Hall, common 

 Ectenodesma hirostratum Hall, rare 



Spirifer pennatus var. posterus has very long wings, while casts of 

 the ventral valves are without median septum. Individuals of this 

 species are very abundant and well characterized. The forms referred 

 to Productella speciosa possess small umbos, and have rather thickly 

 set spines, with small bases. 



At 1,400 feet a conglomerate occurs which contains Camarotoechia 

 congregata. This seems to be identical with a simularly situated 

 conglomerate farther north, which contains Camarotoechia congregata 

 and which will be shown to be referable to the horizon-bearing Spirifer 

 mesacostalis at other locahties. At 1,750 feet above the base of the 

 Jennings Spirifer mesas trialis appears. 



The faunules Qccurring between 520 and 1,000 feet altitude con- 

 sist of species all of which occur in the Ithaca fauna of New York or 

 Pennsylvania. Spirifer pennatus var. posterus, Productella speciosa, 

 Pugnax pugnus and Schizophoria striatula are characteristic species 

 of the Ithaca fauna of New York, while J. M. Clarke cites Leiorhyn- 

 chus globuliforme as occurring frequently in the same fauna. Cyrtina 

 hamiltonensis and Ectenodesma hirostratum are cited by Kindle and 

 Williams from the Ithaca fauna at Catawissa, Pa. The entire asso- 

 ciation therefore consists of species occurring elsewhere in the Ithaca 

 fauna and contains no diagnostic Chemung forms. Its position is 

 above the Naples fauna and below the Spirifer disjunctus fauna of 

 this section. Thus both in composition and position it appears to be 

 referable to the Ithaca fauna. 



In order to ascertain whether Chemung forms may not be mingled 

 with these species at other places, a careful examination was made of 

 similar horizons in a number of localities. 



