Indian JloumU and Skulls hi Michigan. 35 



tain about it that may be readily demonstrated : the fossil sponge 

 found iu the Niagara Group, near Waldron, Indiana, is not siliceous, 

 but is calcareous ; moi-eover, it belongs, without much doubt, to the 

 genus Adylospongia, though I have not seen one polished, to show the 

 spicula, and bears the name among collectors of the Adijlospongia prw- 

 morsa. While the Adylospongia, from the Niagara Group, iu Tennessee, 

 is siliceous, it is calcareous from the contemporaneous strata in Indi- 

 ana. The i:)hilosophy of its fossilization is clearly shown in the article, 

 iu tliis journal, by Harvey B. Holl, of England, and the error of Dr. 

 Roemer, in supposing them to have been siliceous while living, clearly 

 pointed out. It "was but natural for Dr. Roemer to have supposed 

 them all to be siliceous, because he saw none others among his collec- 

 tion from various parts of the world. His mistake, however, illus- 

 trates the danger of generalization from a limited number of facts. 



Indian Mounds and Skulls in Michigan. Residt of Explorations of 

 Mr. Henry Gillman. From the Sixth Annual Report of 

 the Trustees of the Peabody Museum of American Archaeology and 

 Ethnology, Harvard College ; Prof. Jeffries Wyman, Curator. 

 [From Am. Jour, of Science and Arts, January, 1874.] 



A collection made by ^Iv. Henry Gilman, from a mound on the 

 Detroit river, Michigan, explored by him for the Museum, consists of 

 liuman remains and various objects buried with the dead. The latter 

 are of the common kinds, such as stone chisels, one of much beauty, 

 made of dorite, and highly polished, a spear point, arrow points, stone 

 pendants, a stone boring tool, beads and ornaments made of shell and 

 copper, an implement made of an antler, a miniature vase of the size 

 of a common thimble, and two large and perfect vases of the oval pat- 

 tern, and ornamented over the whole surface with cord marks. 



One of the skulls, that of a fully adult person, is worthy of notice 

 for its diminutive size, and for a remarkable extension of the lines 

 for the attachment of the temporal muscle toward the top of the head. 

 The average capacity of the Indian cranium, as given in the tallies of 

 ^lorton and Meigs, is eighty-four cubic inches, and the minimum 

 observed by them sixty-nine cubic inches. That from the Detroit 

 river mound measures only fifty-six cubic inches, or less than sixty- 

 seven per cent, of that of the average Indian. In ordinary skulls the 

 ridges of the temporal muscles on the two sides of the head are sepa- 

 rated by a space of from three to four inches, seldom less than two, 



