Wm. F. Prouty — Meso-Sihirian Deposits of Maryland. 571 



division, on the other hand, is characterized by its branchi- 

 opod fauna. 



The forms noted in the two fossiliferous divisions are as 

 follows : 



From the lower fossiliferous division: 



Buthotrephis gracilis var. intermedia Hall 

 * Anoplotheca hemispherica (Sowerby) 

 Stropheodonta corrugata (Conrad) 

 f Tentaculites sp. 

 Clidophorus sp. 



* Calymene blumenbachii 



* Calymene sp. no v. 



* Ostracods 



From upper fossiliferous division : 

 f Atrypa reticularis (Linnaeus) 



* Leptaena rhomboidalis (Wilckens) 

 Camarotoechia neglecta Hall 



* Chonetes cornutus (Hall) 



* Chonetes novascoticus (Hall) 



* Chonetes tenuistriatus Hall 

 Spirifer radiatus (Sowerby) 

 Bucanella trilobata (Conrad) 

 Calymene clintoni (Vanuxem) 



In Upper Meso- Silurian. — 



While the Clinton fossils seem to have a rather extended 

 range vertically and a more or less local distribution, making 

 a close zonal study of this formation seemingly impracticable, 

 the overlying Meso-Silurian may be divided into five portions, 

 three of which are well-niarked faunal zones. Immediately 

 overlying the top Clinton sandstone and extending vertically 

 sometimes 30 feet, though usually more restricted, is a very 

 prolific faunule, marking a zone called from one of its most 

 widespread and characteristic fossils, the Dalmanites limulurus 

 zone. This zone includes more than one-half of the species 

 described from the whole Meso-Silurian series of Maryland. 

 At Cumberland, where this zone was most studied, the follow- 

 ing species were observed : 



Fauna of the Dalmanites limulurus Zone. 



Anoplotheca hemispherica (Sowerby) 



* Atrypa. reticularis (Linnaeus) 

 Camarotoechia neglecta Hall 



Dalmanella elegantula (Dalman) 

 f Dalmanella elegantula var. nov. 



* Leptaena rhomboidalis (Wilckens) 

 Reticularis bicostata var. nov. 



* Abundant. f Very abundant. 



