﻿Fucoids of the Cincinnati Group. 



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These agents and their effects being the same, it is possible, by studying 

 what is going on in the present age, to picture what went on in past ages. 

 Rain fell as it falls on the earth and washed it away. Water held the sed- 

 iment and deposited it in the same way then that it does now. Rivers rose 

 and fell. Tides ebbed and flowed. Their effects were the same. Sediment 

 was left on the retiring of the waters of rivers, and on the ebbing of the 

 tide. So that as far as the aqueous forces are concerned, their effects may 

 be regarded the same ten million years ago as they were only ten years 

 ago. 



But while the physical agents were unchanged, and their effects were as 

 they still are, the forms of life have undergone a complete and entire rev. 

 olution. Not a single creature is identical with its forerunners of the 

 Silurian and Carboniferous epochs. Yet, though neither the species nor 

 the genera are identical or hardly similar, the general types are much the 

 same. Corals, echinoderms, lamellibranchs, gasteropods, annelids, crusta- 

 ceans, all frequented the Palaeozoic seas. All of them have left their 

 remains in the rocks in abundance ; sometimes so plainly, that there can 

 be no doubt as to their character ; at other times so imperfectly, as to be 

 difficult of determination. And while many students have observed these 

 remains, the observations have not been made as they might have been. 

 The idea seems to have been that every mark was made by a living thing, 

 or was the remains of a species. Sufficient attention does not seem to have 

 been paid to the varying conditions of life, nor to the natural forces then 

 active. It is the object of the present paper to call attention to, and show 

 the true character of, certain marks found in the rocks of the Cincinnati 

 group which have previously been regarded as organic. 



CHARACTER OF FUCOIDS. 



The term "fucoid "' is one which has been used by palaeontologists in i he 

 most indefinite way. It has been applied to all sorts of markings, and, 

 like charity, covers a multitude of sins. Almost every obscure or unde- 

 terminable form has been called a "fucoid," or has been said to be made 

 up of "fucoidal matter." Abused as the word has been, it has come at 

 last to have none of its original significance, and should either be restricted 

 to what are strictly remains of seaweeds, as the term implies, or else dis- 

 carded altogether. The latter would, perhaps, be the better course, and the 

 word Algae substituted in its place. But, at the same time, care should be 

 taken that none but what are the remains of Algae should be referred to 

 the class. 



As this order of plants is known now. there are few indeed, of them thai 



