RAYMOND: CORRELATION OF THE ORDOVICIAN STRATA. 209 



To the writer it would appear that this entire series, including the 

 limestone at the base, belonged to the Phyllograptuschiefer and that 

 we have here Planilimbata limestone and Phyllograptus shales inter- 

 bedded. If this is the case, then the Dictyonema shales, Obolus 

 sandstone, and the Ceratopyge zones are absent. 



The limestone of the section, the Orthocerenkalk, about thirty- 

 seven meters in thickness, is thus subdivided : — 



Orthocerenkalk 



Platyuruskalk. 

 Gigaskalk. 

 Asaphuskalk. 

 [ Limbatakalk. 



Of the Limbatakalk a thickness of only 1.35 meters of dark red 

 limestone was seen, the guide fossil, Mcgalaspis limhata being present. 



In the gray Expansuskalk the following typical fossils were obtained, 

 among others : — 



Mcgalaspis hews. Lycophoria nucclla. 



Asaphus expansus. Orthis callactis. 



Ampyx nasutus. Orthis calligramma. 



The Gigaskalk is a rather thick-bedded red limestone with Mcga- 

 laspis gigas and grades into the red, coarse-grained Platyuruskalk 

 wath the guide fossil, Asaphns platyurus, and cephalopods. Above 

 this is a gray limestone, occupying the position of the Chironkalk of 

 other sections, but without fossils. 



The Graptolithenschiefer have been investigated fully by Hadding, 

 (60) who found, immediately overlying the unfossiliferous gray lime- 

 stone, about eight meters of black shale with layers and lenses of dark 

 limestone, the whole characterized by graptolites and trilobites. He 

 has designated this band as the zone of Climacograptus putillus, and 

 finds there, among other fossils : — 



Didyniograptus superstes Lapw. Nileus armadillo Dalman. 



Diplograptus perexcavatus Lapw. Ogygiocaris dilatata Briinn. 



Climacograptus jndillus Hall. Trinuclcus coscinorrhinus Ang. 



C. scharcnhcrgi Lapw. Telcphus bicvspis Ang. 



Triarthrus becki hinnilis Hadding. Robergia micropthalma Linrs. 



In slightly higher beds, with less limestone and more shale, he 

 obtained, with others: — 



Diccllograptiis sextans cxilis E. & \V. Ogygiocaris dilatata Briinn. 

 Nemagraptus gracilis remotus E. & W. Xileus armadillo Dalm. 



