42 
The Ohio Naturalist. 
[Vol. XIII, No. 2, 
When Prof. Arthur M. Miller visited the exposures at the 
extreme northeastern end of the railway line crossing Goat island, 
he was impressed with the Curdsville facies of the fauna included. 
He found Carabocrinus vancortlandi, Cleiocrinus regius, and 
Glyptocrinus ramulosus, to which have been added more recently 
Reteocrinus alveolatus and Cyclocystoides halli, a typical Kirkfield 
fauna. Among the bryozoans collected at this horizon Dr. E. O. 
Ulrich identified provisionally Batostoma winchelli. Bythopora ef. 
alcicornis. Callopora multitabulata, Eurydictya multipora, Ilomo- 
try pa minnesotensis, Monticulipora (?) cannonensis, Rhinidictya 
minima, and Rli. mutabilis. Apparently there is an admixture of 
Black river with Trenton species, but possibly the real explana¬ 
tion is merely the greater vertical range of various species hitherto 
not found above the Black river. 
The total thickness of the strata to be assigned to the Curds¬ 
ville bed is unknown. From the lowest strata seen on Goat island 
to the highest strata containing an abundance of the columns of 
Glyptocrinus ramulosus, the interval is nearly 30 feet. The 
Carabocrinus vancortlandi layer is about 7 feet above the base of 
this section, and most of the other crinoids and cystids occur about 
11 feet above this level. Stromatocerium is rare in the layer 
immediately overlying the upper Glyptocrinus horizon, but becomes 
common at a higher horizon which is exposed along the southern 
margin of Goat island. Possibly 20 feet would be sufficient to 
cover this interval, and an equal interval might account for the 
strata intervening between this abundant Stromatocerium horizon 
along the southern edge of Goat island and the lowest strata 
exposed along the shore in the eastern margin of Little Current. 
0. Trenton Exposures at Little Current, on Manitoulin 
Island, including Collingwood Formation. 
Immediately at water’s edge, east of Little Current, the 
following bryozoans were collected and submitted to Dr. E. O. 
Ulrich: Arthoclema billingsi, Callopora multitabulata, Dekayella 
trentonensis, Eridotrypa mutabilis. Mesotrypa inf da, M. cf. whit- 
eavesi, Monticulipora arborea, Prasopora simulatrix, and Rhini¬ 
dictya fdelis. The fauna as a whole impressed Dr. Ulrich as 
resembling that in the Nematopora horizon in the upper Prosser. 
While some of the species are found also in the Wilmore, these are 
forms which occur also in the upper Prosser, while conversely no 
forms are seen here which occur only in the Wilmore. A small 
specimen of Strophomena and numerous specimens of Rhyncho- 
trema inaequivalve occur at the same horizon. 
If the abundant Trenton fauna found in the white limestones 
northwest of Collingwood, on the lake front, find any equivalent 
in the Mantoulin area, this must lie somewhere between 20 and 30 
feet above the lake in the section exposed east of Little Current, 
