76 Cincinnati Society of Natural History. 



ties; still others that are still highly problematical. Among 

 the certainties may be placed that which asserts the origin of 

 coal from forests of cryptogamous plants, in what is known as 

 the Coal era ; among the probabilities, that which says the 

 early Cambrian and Silurian seas were filled with algte ; while 

 among the highly problematical statements is that which 

 asserts the preservation as fossils of much of the early algal 

 vegetation. 



When our early searchers began their investigations they 

 frequently met with curious objects which bore no resemblance 

 to animals, and which did not seem to be related in any way 

 to ordinary plants. Finally, Adolphe Brongniart, in 1822, 

 coined the genus Fucoides, into which he placed those 

 fossil objects considered by him to be the remains of algae. 



It is not the intention here to enter into a disquisition on 

 the genus Fucoides. That may be reserved for another occa- 

 sion. It mu.st suffice to say that the genus was eagerly 

 accepted by the grateful students of geology, who forthwith 

 proceeded to unload into it all the objects which were certainly 

 not of animal origin, but which they thought must be the 

 remains of some living thing of by-gone ages. The result of 

 this was that before many years the genus began to overflow, 

 and then, like an overloaded wagon, broke down. Originally 

 designed as a receptacle for alga-, it soon contained an 

 agglomeration of objects which bore no likeness to anything 

 but themselves. Of late years this chaotic mass has been 

 sifted out. Among the debris we find tracks of crustaceans, 

 burrows of worms, trails of moUusks, marks made by trailing 

 tentacles of niedusce, markings made by the tide or waves, 

 rills made by running water, and holes formed by burrowing 

 worms. The study of this mass of material has revealed the 

 fact that tho.se phenomena, which can be seen on the shores of 

 our oceans, lakes and rivers to-day, were just as common in 

 times past. We, therefore, seem ju.stified in a.ssuming that 

 conditions prevailing now were in existence then. 



The conditions governing the preservation of plants in a 

 fossil .state vary greatly. So, too, what may be termed the 

 "expectation" of j^rcservation varies. For example, a leaf or 

 a branch falling to the ground and lying ex]>osed to the 

 elements is far less likely to be ])reserved than one which is 

 ])r()U'cU(l from these destroying agencies. Also, a plant of a 



