RAYMOND: CORRELATION OF THE ORDOVICIAN STRATA. 249 
graptus tenuiramosus, are restricted to that locality and the Fulton of 
the Cincinnati district. Pleurograptus linearis, which is so important 
a fossil in northern Europe, is in this country known only from a single 
specimen found at Holland Patent. Callograptus compactus is also 
known only from Holland Patent. There are varieties of Dicrano- 
graptus nicholson in older shales, but the typical form is restricted to 
the horizon of the Utica of Holland Patent. It is found also in the 
Fulton shale of the Cincinnati district and near Saratoga. In at- 
tempting a correlation of any other fauna with that of the typical 
Utica it must be borne in mind that some of the typical species of that 
fauna are so rare that but few specimens are known. Practically all 
the species of graptolites which are not restricted to the locality at 
Holland Patent are species -of considerable vertical range. The 
occurrence, however, of Pleuwrograptus linearis stamps that fauna as 
younger than that with Dicranograptus clingani and probably equiva- 
lent to the upper Chasmops shale of Sweden. 
The Fulton shale at the base of the Eden at Cincinnati contains a 
graptolite fauna very like that at Holland Patent. Some of the 
species are: — 
Mastigograptus tenuiramosus Climacograptus typicalis Hall, 
(Walcott), C. putillus (Hall), 
Leptograptus annectans Walcott, Lasiograptus bimucronatus timi- 
Dicranograptus nicholsont Hop- dus Ruedemann. 
kinson, 
Associated with these are Cryptolithus tessellatus and Triarthrus 
beckt. In higher beds of the Eden of the same region one finds Dictyo- 
nema arbuscula Ulrich, Mastigograptus gracillimus (Lesquereux), 
Chaunograptus gemmatus Ruedemann, and Climacograptus typicalis 
Hall. 
_ From the above we may derive that the more widespread species 
of the typical Utica (Pleurograptus linearis fauna) are Mastigograptus 
tenuiramosus, Leptograptus annectans, Lasiograptus bimucronatus 
tumidus, and Cryptolithus tessellatus. Climacograptus typicalis, Dicran- 
ograptus nicholsoni, and Triarthrus becki are also species which though 
not strictly restricted to the Utica, are to be found in every outcrop 
of that formation. 
From the above it is evident that while some of the graptolites have 
a long range in the black shales of New York, there are species which 
seem to be characteristic of certain horizons. Thus we have in the 
