Editor's Table. 
243 
esee Shales'' of eastern sections ; and the present writer is the first 
9th, That in the Iowa section is represented (so far as is at pres- 
ent known) the extreme western, attenuated, representatives of 
the eastern " Marcellus Shales" and " Genesee Shales" 
loth. That the upper Hamilton (blue clay) is succeeded upward 
by a stratum of Argillaceous Shales, which everywhere occupy the 
highest position in the Devonian series in the State, and has an 
observed thickness of forty-five feet ; although known to have at- 
tained a greater thickness prior to the glacial period, during which 
time they were more or less extensively eroded. 
nth. That these Shales, which have been designated (provision- 
ally) by the writer, in all his preliminary reports, as the *' Rock- 
ford Shales," constitute, lithologically, stratigraphically, and biolog- 
ically, a rmv and heretofore unrecognized (as such) group of 
strata, and which is not developed in any other area in North 
America, or Europe ; although all contain links of evidence which 
demonstrate its Devonian age, and for which the writer has in 
name Hackberry Group. 
EDITOR'S TABLE. 
The Philadelphia Academy of Natural Sciences has recently 
attacked the problem of original research in a practical manner. 
For many years the activity of the institution was restricted 
to the publication of work produced by scientific specialists on 
material contained in their own collections, and in the muse- 
ums of other institutions. To this function it subsequently 
added that of giving instruction to classes in the natural 
sciences. We have often pointed out that the former hne of 
activity is not enough for an institution which at one time 
was the only academy of original research in this country; and 
we have also expressed the opinion that the teaching of 
the natural sciences to classes of beginners, is not one of its 
proper uses. We have schools for teaching elsewhere, but 
