6 FOSSIL MARINE PLANTS LESQUEREUX. 



cient seas;* one also by Delgado on the Bilobites aud other fossil re- 

 mains of the Silurian of Portugal ; t aud still others in opposition to 

 the opinion of these authors, especially the memoirs of Professor Na- 

 thorst, of Stockholm, on the tracks of invertebrate animals and their 

 paleoutological importance.! The first two paleontologists named, 

 admitting the vegetable origin and uatureof the fossil remains in ques- 

 tion, have supported their opinion by splendid figures aud admirably 

 detailed descriptions of these fragments, especially the Bilobites, which 

 theyconsideras vegetables of the ancient seas ; while Professor N"athorst, 

 following an original and quite different method of research, has pro- 

 duced upon sand, soft clay, or muddy matter, by mechanical agency, the 

 tracks of insects, mollusks, crustaceans, etc., the movement of water 

 upon the shores, the action of rain, of currents, etc., traces in relief or 

 impressions very similar in appearance to many of those which have 

 been described by botanists as fucoidal remains, and has presented by 

 photography upon numerous plates the remarkable result of his experi- 

 ments. 



I am not called upon to discuss in this short article the nature of 'the 

 evidence afforded by these memoirs in support of the conclusions of 

 these authors, as both opinions are legitimate when partially applicable 

 or sustained by facts, while they are in the same way rightly contra- 

 dicted by others. 



In generalizing on a subject like this the evidence is interpreted ac- 

 cording to the views of each of the contesting parties, and partly sup- 

 ported by facts unknown or not examined by the others. The student 

 called to determine the nature of as yet unknown fossil remains has to 

 use his own judgment, and to describe as reasons for his opinion the 

 characters on which his determinations are based. 



DESCRIPTION OF THE SPECIMENS. 



Halymenites Herzeri sp. nov. 



PI. I, Figs. 1, la. 



Fragment of stem or frond, cylinrlrical, simple, undulately curved, as flexible in 

 its original state, immersed in the limestone, split lengthwise and exposing its inner 

 structure, which is composed of a tubular, central hollow, filled in its petrified state 

 by amorphous hard calcareous matter, bordered with a thick coating or cortex of less 

 compact cellular matter, intermixed with a large number of black, perfectly round 

 dots, spores, or reproductive gemmules, one-fourth of a millimeter in diameter or less. 



The preserved part of the frond is 18' '" lon^'', 6'"'" in diameter ; the 

 central (originally hollow ?) part 2^™""; the spores, extremely numerous,. 



* Les organismes probl6matiques des aucieunes mers, Paris. 1884. 



t fitude sur les Bilobites ct autres fossiles des Quartzites de la base du Systeme Si- 

 lurique du Portugal, par J. F. N. Delgado. Lisbonne, 1886. 



tOm spar af nagra evertebrerade, etc., in Koenigl. Sveuska Vetenskaps-Aka- 

 demiens Ilandinger, B. 18, No. 7, 1886, [with separate edition of this work trans- 

 lated and abridged in French as "Nouvelles observations sur des traces d'animaux 

 et autres ph^nomenes d'origine purement m^canique d^critscomme Algues fossiles," 

 par A. G. Nathorst. 1886. ] 



