PROCEEDINGS OF SCIENTIFIC SOCIETIES. 505 
similar t This arrowhead was found seven feet beneath the sur- 
face in a ditch excavated in the southern part of Washtenaw county. 
The coe remains found near Tecumseh, but a few miles distant, lay 
but two and a half feet beneath the surface. The Adrian mastodon was 
buried but three feet deep. 
The second note related to the occurrence of enormous beds o 
bog iron in the upper peninsula of Michigan, on the tributaries of the 
Monistique river. It occurs in a half desiccated bog covering several 
townships. It is of remarkable purity, and of great but unknown depth. 
It lies directly in the track of the projected railroad, intended to connect 
the North Pacific Railroad with the railroad system of Michigan. The 
ore can be pe down er ERGEN and its tributaries, to Lake Michi- 
gan, in the immediate vicinity of an excellent harbor. This immense 
dipòsit is enr doc sete’ from the desintegration of the hematites 
and magnetites of the contiguous region on the West. sie ore will 
possess great value for mixing with oes other Lake Superio es. 
The third note was on the discovery of an ancient salle of Lake 
Superior. Following the White Fish river from the head of Little Bay 
de Noc, we find it occupying a broad and deep valley walled in on both 
sides by limestone cliffs attaining an elevation of one hundred and twenty 
feet. The head waters of this river literally interlace with those of the 
Au Train river, which runs north into Lake Superior. Here is a vast 
valley of erosion but little elevated in any part above the present level 
L gh thi 
ear the head of the valley, point North and South. In short, the evi- 
dences lead to the conviction that a vast glacier stream once traversed 
this valley and was probably the agency by which it was excavated. 
Little Bay de Noc is but the prolongation of this valley at a lower level; 
and, indeed, the whole basin of Green Bay seems to be but a phenomenon 
of erosion belonging to the epoch of the same glacier system. 
Prof. E. D. Corr read a paper ** On the structural Characteristics of the 
Cranium in the lower Vertebrata (Reptiles, Batrachia and Fishes),” giving 
à new systematic arrangement of the Reptilia, and determining for the 
first time the struc nm of the posterior regions of the crania in Dicy- 
nodons and Ichthyosa 
He first pointed out cen homologies of the squamosal bone, stating that 
identical, with the “ temporo-mastoid ” of the frog, and the preoperculum 
of osseous fishes, by comparison with Lepidosiren. This was proven by 
AMER. NATURALIST, VOL. IV. 64 
