80 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [bull. 165. 
Fauna of 1099 B 1, 2, 3, 4, and 5. 
1. Rensselaeria (Beachia) n. sp. cf. sues- 
sana. 
2. Spirifer raricostus Billings. 
3. Spirifers of the arrectus and gaspensis 
form. 
4. Avicula cf. securiformis. 
5. Chonetes canadensis. 
6. Bellerophon. 
This fauna indicates a horizon nearly equivalent to the early stage 
of the Graspe* sandstone, which the Canadian geologists have correlated 
with the Oriskany. It is undoubtedly Eodevonian, and differs from 
the typical, more western, Oriskany fauna in the general facies of the 
species. 
The abundant and great development of the Rensselceria is a notable 
feature of the fauna. The specimens are provisionally referred to 
R. suessana, which they most nearly approach among the American 
forms in generic characters. Comparisons with the figures of Tere- 
oratula strigiceps, referred by Keyser and others to Rensselseria, as well 
as study of the faunal associates, lead the writer to the opinion that 
the Maine specimens may be identical with the European form. The 
name Rensselceria mainensis is provisionally proposed for this form. 
This species is not reported from the Lower Helderberg, and is, so 
far as the reports of its range are known, indicative of the Lower 
Oriskany. As is noted in the account of the Moose River sandstone 
fauna, this same species occurs in western Maine. The association of 
species there found corresponds more closely with the fauna of No. 8 
of the Gaspe limestone series of the Canadian reports. The spirifers 
common are the forms called by Billings Spirifera raricosta and 
Spirifera cycloptera. This Moose River sandstone fauna, as stated on 
page 88, has been called Oriskany by Hitchcock, and the corresponding 
fauna of Limestone No. 8 and of the base of the sandstone of the Gaspe 
series is also called Oriskany by Billings. 
Both these faunas and the Chapman sandstone faunas belong more 
nearly with the Lower Oriskany of Becraft and the southern Appa- 
lachians than with the fully developed Oriskany fauna of New York. 
After the manuscript of this bulletin was finished and handed in to 
the Survey the author continued his investigation of the Chapman 
sandstone fauna, with the result of determining its correlation with 
the ("Tilestone") Downtonian fauna of the Welsh standard Silurian. 
The importance of this identification to a correct understanding of the 
Maine Paleozoics furnistfes sufficient reason for the insertion at this 
place of the more significant parts of the paper in which the results 
were first announced. 1 
The identification of the Chapman sandstone fauna of Aroostook 
County, Maine, with the typical Ludlow "Tilestone" fauna of Mur- 
iThe Silurian-Devonian boundary in North America; I, The Chapman Sandstone fauna: by Henry 
S. Williams: Am. Jour. Sci., March, 1900, 4th series, Vol. IX, pp. 203-213. 
