3i»C Tlie Ameviccuh Geologist. Decomber, i89~> 
|t()i-t of tlio 'rexiis(Teolugiciil Survey, pp. i,.\\.\iii-i,\.\xvjii and pj). loti- 
141; witli the American .lotirnjil of Hcience, April, 1887, and otlier 
papers of mine referred to in this communication. 
Tiie valuable writings of Dr. C. A. White, as well as those of Prof. 
Jules IMarcou (who made the llrst correct determination of the Lower 
(•retaceous age of the beds of northern Texas), are likewise entirely 
ignored in this report.- 
There are also several erroneous statements in the review concern- 
ing the range of sjiecies, but these \vill be reserved for future com- 
ment. IvOBT. T. Hill. 
W(i>^l,;u<jtn„, I). r.,yor.jb: isfu. 
N'oLOANic DUST IN IvANSAS AND INDIAN Terkitoky. — The peculiar 
volcanic dust or sand mentioned by professor Todd in the November 
Geologist occurs, as is well known, in various places in western Kan- 
sas. I found it, as early as 1874, in Norton county, and professor St. 
John records it from several localities in tlie extreme southwestern 
part of the state. During the past year I have received specimens 
from the Indian Territory, south of Arkansas City, and from a few miles 
southwest of Galena, a locality considerably further east than Omaha. 
The sand in both these latter localities is rather more grayish in color 
than that from the northwest, but otherwise is identical. The gentle- 
man who gave me the specimen at Galena, stated that the deposit is 
many feet in thickness at this locality. S. \V. A^'illiston. 
Ldirrencc, Katisdii, Xor. ,?,?, ISft:". 
Classification of the cephalovoda. The November number of 
the American Geologist contains a note (p. 327) on the comparison 
Tables of Classification issued in the July number of Froc. Geol. Assoc. 
London, to illustrate the Presidential address. I do not wonder at 
your saying "Bather's is the most remarkable mainly on account of 
its brevity." As you have further reprinted the words that purport 
to represent my classification, I should like to have the opportunity 
of saying that I am not responsible for that Table, and that it does 
not properly represent any view's held by me now or formerly. 
Though no actual classification of the Cephalopoda was ever pub- 
lished by me. still the cancelled Table did represent the views held by 
me in 1888 and expressed in various papers about that date. The 
views to which I w^as led w^ere largely influenced by the ideas of 
American writers, and I should be sorry to see a misleading account 
of those view^s disseminated, without correction, by an American pub- 
lication. Therefore I ask you to be good enough to print the accom- 
panying table. Not having been able to read all the recent literature 
on Cephalopoda, I cannot say that I regard these as the best possible 
views at the present day ; but I regarded them as the best views pos- 
*For a resum<3 of Mr. Marcou's early determination of the Lower 
Cretaceous in the Texas region, see Bulletin 45, U. S. Geological Sur- 
vey • The I'resent Condition of Knowledge of the Geology of Texas. 
By Pvobt.T. Hill. 
