266 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
Stictoporella, Rhinidictya, Phylloporina, and Clitambonites beds 
(Black River to Middle Trenton) of Minnesota, was identified from 
the Kunda of Russia. These forms are evidently of little value in 
direct detailed correlation, since the two species found in B,, would 
correlate that formation with the Upper Trenton, while the two found 
in B,,, correlate that formation with the Black River and Lower 
Trenton. One of the species has a range equal to almost the whole 
Ordovician of Russia, and another has a very long range in America, 
so that no very valuable conclusions can be derived from them. 
In considering the Bryozoa, it must be remembered that as yet only 
a few specimens belonging to the genus Nicholsonella, have been 
found in the American Beekmantown, and that the fairly large bryozoan 
fauna of the Chazy is as yet undescribed. The comparison of the range 
of genera in America and Russia does not, therefore, mean much, for 
many of the American genera now supposed to start in the Black River 
will probably be found to have their beginnings in the Chazy. There 
are, however, one or two interesting points to be noted in this connec- 
tion. Bassler distributes the twenty-six species which he describes 
under eighteen genera (compare with seventy-seven species of trilobites 
in eighteen genera, and forty-five species of brachiopods in fifteen 
genera). Of these eighteen genera, only three are not found in Amer- 
ica (compare with eight out of eighteen in the trilobites and eight of 
fifteen in the brachiopods). Three more are very peculiar, in that 
their American range begins much later than in Russia. One of them 
is known in this, country from the Richmond to the Mississippian, 
another from the Niagara to the Coal Measures, and the third is 
wholly Devonian and Mississippian. A single one is found in the 
American Beekmantown, and the remaining eleven are known from 
the Stones River or Black River to the Richmond, excepting for one 
or two which do not start till the Middle or Upper Trenton. Looking 
over the table showing the range of the various species in Russia, we 
find that four species are confined to B,,, one is confined to B,, and 
B,,, nine are found only in B,,,, eight pass from B into C, but do not 
extend further, and that three begin in B and continue into D, E, or F. 
Thus, among the Bryozoa, there are only five species common to B,, 
and B,,,, and of these only one does not continue into C, while there 
are eleven common to B and C, which is very unlike the condition 
which obtains among the other classes. For instance, in the seventy- 
seven species of trilobites, nineteen are common to B,, and B,,,, and 
only thirteen pass from B into C, and some of these cases must be 
considered as doubtful, since they come from that district on the 
