On Problematic Orynihm* 



ON PROBLEMATIC ORGANISMS, AND THE PRESER- 

 VATION OF ALGJE AS FOSSILS. 



For many years past the subject of the animal or vegetable 

 nature of a large class of fossil bodies has been a matter of 

 discussion between two schools of geologists. One of these 

 considers as fucoids or alga? a certain group of forms whose 

 members do not present any organic appearance, but which in 

 the early days of their study were made to do duty as plants, 

 and which consequently still pose as such. The other class 

 refuses to recognize the fossils as the remains of plants, and 

 point out the analogy they present to worm trails, worm bor- 

 ings, animal tracks or marks of inorganic origin. These 

 schools are represented on the fucoid-side by Saporta, Delgado 

 and others, and on the opposite side by Nathorst, Dawson and 

 others. 



The attention of the present writer was first attracted to 

 these fossil forms by their abundance in rocks of Lower Silu- 

 rian age in the vicinity of Cincinnati. Ohio, the geologists 

 there universally regarding them as plants. During the sum- 

 mer of 1884, while engaged in arranging the collections of the 

 Cincinnati Society of Natural History many specimens were 

 studied; and as supplementary thereto the markings made by 

 various insect larvae, shells, or by running water upon the mud- 

 flats of the Little Miami river. The result of these studies 

 was a paper on the " Fucoids of the Cincinnati Group," pub- 

 lished in the Journal of the Cincinnati Society of Natural 

 History, in October 1884 and January 1885. In this paper 

 some of these so-called fucoids were referred to inorganic 

 causes ; many more to trails and burrows, and some few to 

 graptolites. None were considered indubitable alga?. Some 

 of the opinions in that paprr lvijuin t odi ration, but no addi- 

 tional information has caused the opinion that they are not the 

 remains of alga?, to be changed. 



