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Cincinnati Society of Natural History. 



are likely to be preserved as fossils.* Consisting, as they do, of thin cell- 

 ular, membraneous tissue, sometimes with a central rib, sometimes lacking- 

 it ; with or without a stem ; sometimes coarse and sometimes formed of deli- 

 cate thread-like fibers, there are comparatively few which seem to be capa- 

 ble of preservation. There is no reason to suppose that the ancient pro- 

 genitors of the Algae were more likely to be preserved than are the modern 

 prototypes; and it should be considered rather a matter of surprise to find 

 any in a fossil state, than a thing to be expected. The fact is, that the 

 majority of the remains which have been called "fucoids," and thus referred 

 to the Algae, are not plants at all, and are in some cases not even of an 

 organic nature. When such is the case, and when mud marks, annelid 

 trails, burrows, trails of gasteropods and lamellibranchs, and casts of artic- 

 ulate tracks have been called fucoids, it is time to investigate the state of 

 affairs, and endeavor to settle the disputed question as to what shall be 

 called Algae and what not. 



There can be no possible objection to describing and figuring the trails, 

 tracks or burrows of animals which lived in long past ages as long as they 

 are considered as trails or burrows. But there is considerable objection to 

 calling them and referring to them as Algae, when they have no connection 

 whatever with plants. The rocks of the Cincinnati group and the Clinton 

 group are full of markings of various sorts, much more so in fact than the 

 higher formations. As they are generally of an obscure and indefinite 

 character, they have been either largely overlooked, or else studied in a 

 careless and superficial manner. For while corals, crinoids, mollusks and 

 crustaceans have been carefully studied, the large field occupied by the 

 above-mentioned markings has been disregarded. Yet they are at the same 

 time valuable as showing one very important thing, and that is, that the 

 conditions of nature were the same, or very similar, to those we find at 

 present. 



* Note. — In regard to the preservation of Algae in modern times, Lesquereux, in 

 the Thirteenth Annual Report of the State Geologist of Indiana, 1883, P art 

 p. 26, says : " When rapidly decomposed under atmospheric influences, the marine 

 plants pass to a fluid state, or when coriaceous, they are dissolved under the alter- 

 nate action of dryness and humidity. The heaps of wrack, or of hard species of 

 marine Algae thrown upon the beach by the waves, do not become compact and dry, 

 and can never be used for fuel, like peat ; they gradually pass at the base of the 

 hunks into a half-fluid matter, which percolates through the sand." Now it is a 

 peculiarity of the remains which have been referred to "fucoids," that they are found 

 on what were sea-beaches, where they would be exposed to the "alternate action of 

 dryness and humidity," and, therefore, be little likely to be preserved. The asser- 

 tion that they were exposed on sea-beaches will be referred to later on and proved. 



