Geology and Mineralogy. 485 
“The Trenton Group is not exposed at Cincinnati, nor at any 
point in Ohio west of the city, but we think it is probable that 
k e Ohi 
city, and in the excavations near the mouths of the streams which 
enter the river east of the city. Consequently all the Lower 
Silurian rocks in Southwestern Hee belong to the Hudson sat 
the 
“The conclusion to which we have come is, that all the Lower 
Silurian rocks which we have had under onsideration, are to be 
referred to the Trenton, Utica Slate nee udson River Groups, 
and that the name ‘Cincinnati Group’ should be dropped, not 
only because it is a synonym, but because its retention can sub- 
serve no useful purpose in the science, and because it will, in the 
future, as in the past, lead to erroneous views and fruitless “discus- 
sion. And we would add that so far as any investigations of these 
rocks have been made, they have not oo to any other or further 
subdivisions than those which we have ado opted, and which have 
This Report, besides appearing in the et onbbtioe of the Cincin- 
nati Society, is also published in the tenth Annual Report of the 
Geological Survey of Indiana, where it is followed by a long list 
of the fossils found over the region referred to, in the Hudson 
River, Utica Slate and Trenton Groups, by 8. A. ‘Miller of Cincin- 
2. Atlas to the Coal Flora of ea tenn and te? Carbon- 
iferous SS throughout the United States ; by Lxo Lus- 
in advance of the volume of deansiadve text chen are ree 
remarkable beauty and perfection. The drawings wih prepa 
with great care and th raving is excellent. To Mr. Lesque- 
Singing? of Pennsylvania, who have had the volume published 
nm such admirable style, the thanks of all friends of see 
ical botany, the world over, will be given without stint. 
work at once becomes the necessary hand-book for all who woud 
study American coal plants. The atlas contains figures of 260 
species which have been named and described by Mr. uereux, 
and of these 122 are now for the first time figured. 
Of his modifications of classification—such as his new genus 
