1885. ] in Pennsylvania and New York. 651 
but the aner is found both above and below the stratum contain- 
ing the Ort 
IV. 
Reverting to the preface of G, we read on page xxii this 
remark, apparently by the State geologist : 
“ Halysites catenulatus [the common chain- coral] i is found aiite 
out of its natural place; at one locality only it is true, but 
such abundance as to make upa large proportion of the Genty 
feet pi Ees through which it is found.” 
. Logan recognizes it as low as the Trenton lime- 
stone, A I have seen a form or variety of the same in the Hud- 
son River group of Green bay,' but no one has ever before found 
it above the Niagara 
Professor Lesley adds very justly : 
“Whatever may be the difficulty of distinguishing S. disjuncta 
from S. mesostrialis, it is quite impossible for any one to mistake 
Halysites catenulatus, the characteristic form of the Niagara ax 
stone all over the United States and Canada, and also of the cor- 
responding Wenlock of Europe. 
In these passages there are obvious traces of the vicious rea- 
soning already condemned. The “natural” place of a fossil is 
surely that in which it is found. Its “ canonical” place may be 
very different. Now of the occurrence of Halysites catenulatus in 
the Lower Helderberg limestone at the place mentioned by Pro- 
fessor White, there cannot be the slightest doubt. The obvious 
character of the fossil, such that every tyro in paleontology is 
acquainted with it, precludes all chance of mistake in its identifi- 
cation. The position of the limestome bed in which it was found 
is equally decisive against stratigraphical error. It overlies several 
hundred feet of red shale and sandstone, which are the equiva- 
lent of the Onondaga shales of New York—the Salina shale or 
Salt group, as they are often called. 
The correlation of these has been satisfactorily determined in 
Middle Pennsylvania, and the evidence, both stratigraphical and 
paleontological, may be seen in the writer's report on Perry 
county (F,). It is proper to add here that the above statement 
concerning the place of the bed is made from personal knowledge, 
the ground having been visited for the purpose in company with 
Professor White. 
1 Some inconsistency exists between this statement and that on p. xxv. “ Professor 
Hall has given himself infinite trouble to obtain the data on which rests the proof 
that Æ. catenulatus never occurs except in Niagara and Clinton rocks.” 
2 Letter from Professor Hall. : 
