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: — 
Platyuruskalk. 
Gigaskalk. 
Asaphuskalk. 
Limbatakalk. 
Of the Limbatakalk a thickness of only 1.35 meters of dark red 
limestone was seen, the guide fossil, Megalaspis limbata being present. 
In the gray Expansuskalk the following typical fossils were obtained, 
among others: — 
Orthocerenkalk 
Megalaspis heros. Lycophoria nucella. 
Asaphus expansus. Orthis callactis. 
Ampyx nasutus. Orthis calligramma. 
The Gigaskalk is a rather thick-bedded red limestone with Mega- 
lass gigas and grades into the red, coarse-grained Platyuruskalk 
with the guide fossil, Asaphus 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: — 
Didymograptus superstes Lapw. Nileus armadillo Dalman. 
Diplograptus perexcavatus Lapw. Ogygiocaris dilatata Briinn. 
Climacograptus putillus Hall. Trinucleus coscinorrhinus Ang. 
C. scharenberg. Lapw. Telephus bicuspis Ang. 
Triarthrus beckt humilis Hadding. Robergia micropthalma Linrs. 
In slightly higher beds, with less limestone and more shale, he 
obtained, with others: — 
Dicellograptus sextans exilis E.& W.  Ogygiocaris dilatata Briinn. 
Nemagraptus gracilis remotus E. & W. Nileus armadillo Dalm. 
