(3o Tlie American Geologist. January, i899 
One admirable feature of this volume is the profusion of plates, in 
which neither pains nor expense has been spared. Four plates are 
given to the new species Brooksella, eighteen to Laotira, three to 
Dactyloidites, three to the Swedish Medusse, two to Eophyton, seven 
to the Jurassic species of Bavaria, one to Medusichnites, etc. There 
are also twenty-five wood cuts scattered through the text. 
On the whole this volume is a most important contribution to a 
branch of paleontology which is scarcely within reach of the ordinary 
student, but there are some points on which one would desire further 
information. ^Ir. Walcott has suppressed the genus Medusites and 
substituted the new genus Medusina. on the ground that the former 
was fotmded in error; i. e., that the type species was really a Lumbri- 
caria. Medusites has been used for thirty years past, and by such men 
as Kner. Leuckart, Heeckel, Nathorst, F. Schmidt and von Ammon. 
and with the means of illustration at his command it would have been 
more satisfactory if Mr. Walcott had reproduced Germar's original 
figure and description; then the establishing of the new genus would 
have been more satisfactory and convincing. 
Another thing which seems to come up in this connection is the 
genus Eophyton. This name was given by Torell on the supposition 
that the objects represented were plants, not mere sea-weed, but 
plants of high organization, comparable to Cordaites. 
Very few who have given these objects careful study will agree 
with Torell as to their cause, or think they are plant remains of any 
kind. Mr. Walcott himself does not think so. Here, then, is a 
species whose name conveys an erroneous meaning, yet the author of 
this work, while he has dismissed Medusites as founded in error, re- 
tains Eophyton. 
It would be satisfactory also to some readers of this volume if a 
little more time had been given to explain why the objects referred 
to Medusichnites are thought to be of inorganic origin; the reasons 
given in the original description for supposing them to be of organic 
origin, are not in any way met* 
One might also raise a protest against the practice inaugurated 
by Dr. Nathorst of making tools whereby to imitate natural markings, 
as, for instance. Cruziana; not because there is anything wrong in the 
act, but because the resulting impressions are apt to be misinterpreted. 
The stiflf prints left by these tools, do not in any way represent the 
infinite variety of mood in Cruziana, as shown in the varying trails 
of a single species. The prints made by such tools are about as near 
to the natural object in appearance, as the wood-carver's rose or 
thistle are to these flowers as they bloom in the field. Akin to this 
method is that of producing trails of Medusne by artificial means and 
n-aking them on a wet emerged surface, in place of the fine submerged 
mud of the sea-bottom; the motions and markings in the emerged 
surface are involuntary, and not the natural motions (of the tentacles 
of a Medusa, for instance). There is always the possibility of intro- 
*Trans. Roy. Soc. Can., Vol. viii, sec. IV, p. l-l-'j. 
