1896.) Geology and Paieontology. 941 
Their increase in number ‘has not been due to subdivision of primitive 
teeth as supposed by Kiikenthal, nor is it a survival] of primitive condi- 
tions, as supposed by Ameghino, but it is probably a repetition of 
similar structures due to an extension of the dental groove and dental 
lamina, following the gradual elongation of the maxillary and pre- 
maxillary bones, proceeding contemporaneously with degeneracy of the 
teeth themselyes—E. D. Corr. 
Eozoon canadense.—In recent numbers of the Geological Maga- 
zine, Dr. Dawson cites the evidence to date for the animal nature of 
Eozoon. Briefly summarized, the facts are these: (1) The rocks of 
the Grenville series, where the fossil in question occurs most abund- 
antly, belong to a sedimentary formation. (2) They form a great cal- 
careous system comparable with the metamorphosed Paleozoic calcare- 
ous beds of organic origin in petrological and chemical character. (3) 
New material showing more plainly the structure of the canal systems 
and tubes, evidences a definite plan of macroscopical structure. (4) 
Late discoveries of Archaeospherinae and other objects supposed to be 
organic in pre-Cambrian rocks in Canada and in Europe afford, to 
some extent, corroborative’ evidence i in favor of Eozoon. (Geol. Mag. 
1895.) 
Thickness of the Coal Measures.—<According to Mr. J. C. 
Branner, the total thickness of the Coal Measures (Pennsylvanian) sedi- 
mentsin Arkansas is greater than that of the sediments of the same age 
in other parts of the country or of the world. He gives the following 
table of comparison: Arkansas, 23,780 feet ; Nova Scotia, 16,000 feet ; 
Utah and Nevada, 16,650 (?) feet: Indian Territory, 10,000 feet. Mr. 
Branner finds a reason for the great thickness in the drainage of the 
Continent during Carboniferous times. “The rocks of this series in 
Arkansas afford fossil evidence that this part of the Continent was prob- 
ably not much above tide level. The drainage from near the Catskill 
Mountains in New York flowed south and west. The eastern limit of 
the basin was somewhere near the Archean belt from New England to 
central Alabama. This Appalachian water shed crossed the present 
channel of the Missouri from Central Alabama to the Ouachita uplift, 
and the drainage flowed westward through what is now the Arkansas 
Valley, between the Ozark Island on the north and the Arkansas Is- 
land on the south.” (Amer. Journ. Sci., Sept., 1896.) 
Geological News.—Patrozorc.—An accumulation of fresh ma- 
terial from the Ichthyologic fauna of the Cleveland Shales, Loraine 
County, Ohio, has enabled Mr. C. R. Eastman to determine the rela- 
