8 CORRELATION OF GEOLOGICAL FAUNAS. [bum,, mo. 
sanction and financial assistance the necessarily slow process of accu- 
mulating the statistics lias proceeded. At the outset Major Powell, 
then Director of the Survey, and Mr. Charles T). Walcott, then in 
charge of Paleozoic paleontology, gave their valued encouragement. 
The task was a large one, but its importance was also great. A sin- 
gle person could not expect in a lifetime to execute the whole work 
required to solve the problem, and therefore graduate students at Cor- 
nell University, and later at Yale, seeking practice in geological inves- 
tigation, were interested in the work, and original research along these 
lines was intrusted to them. A large amount of statistics has been 
thus gathered. 
These investigations have now been going on for twenty years, and 
numerous geologists have taken part in them. In the year 1885 a 
brief report of the general results attained up to that time was made 
before the American Association for the Advancement of Sciences 
At that time ten of the sections had been run, viz: Cuyahoga, Ohio; 
Painesville, Ohio; Girard, Pennsylvania; Chautauqua, New York- 
Pennsylvania; Genesee, New York-Pennsylvania; Canandaigua, New 
York; Cayuga, New York; Tioughnioga, New York; Chenango, New 
York; Unadilla, New York. The fossils were collected from the 
separate faunules, and certain general conclusions were then evident. 
Since then Messrs. Prosser, Clarke, Darton, and others have pushed 
the sections farther east, and they have been extended, with the aid 
of Messrs. Van Ingen, Weller, and Kindle, into Missouri, Arkansas, 
Kentucky, Indiana, Virginia, and West Virginia. Messrs. Geiger and 
Sayles have added collections from the Appalachian region. The 
Maryland geological survey is adding to the statistics for Maryland, 
and investigations are now going on in many other regions of the 
United States. Preliminary study of most of the collections has been 
made. The investigations for some pail of the field have been car- 
ried much further than others, but the undertaking has now reached 
a stage in which it is possible to exhibit the general bearings of the 
results upon the whole field of stratigraphical geology and to state the 
principles upon which the investigations have proceeded, as well as to 
suggest at least what may be expected in the future, when the facts 
shall be fully elaborated. 
In the preparation of this report I have been obliged to refer often 
to the statistics already gathered. Some of them, accumulated by 
myself or under my direction, have been published. Other statistics, 
in the form of unpublished notes, compiled in the course of elabora- 
ting the collections, have also been freely consulted. In addition to 
these sources, the reports of others working in the same field have 
been used, and for all such statistics I am deeply grateful to the 
contributing authors. The bibliographic list is large, and may be 
"( >n the classification of the Upper Devonian: Proc. Am. Assoc Adv. Sci., Vol. XXXIV. L886, 
pp. 222-234. 
