276 Scientific Intelligence. 
as genera, they appear one after another through the successive epochal 
centres, becoming multiplied in numbers and perfect in form. Then they 
lessen in numbers, dwindle in size, and finally disappear. 
30. There is a close similarity in New York and Wales in the incre 
ment and decrement of Zoophyta, Bryozoa, Echinodermata, Brachioj 
&c.; that is, these fossils are numerous and few at the same points of the 
Silurian scale. 
pp., " 
Columbus had reached a depth of 1858 fect early in last December i 
the first 23 feet the material passed through was sand, clay and GY 
rived to the De’ 
nian; 1154 feet Columbus limestone, probably Upper a wt 
of ge 
depth of 764 feet,) limestone shales with salt water at 675 feet; ert 
fect of pitches > ab » Uti eae 
stone be the equivalent of the Trenton limestone, Utica slates oy mia 
rock LJ 
d Us 
in Ohio, © 
other States en 
1. Synopsis des Hchinides Fossiles ; par E. Duson. 1 oh 0%) oe 
490 pp. 8vo, with 1 vol. of 44 8vo plates, Paris and Wiesbade 
le, and ‘contains descriptions of 1415 species of all g 
ages, with a very large number of fine figures on the a crowded pis 
