Siudit's in Problematic Organisms. 65 



pointed out in a paper published in the Memoirs of the 

 Museum-^- this group of fossil vegetables under the name of 

 Fucoidcs, and I announced then the work that I publish now. 



The examination that M. Agardh gave to these fossils at 

 the time of his stay in Paris, (in January, 1821,) and the 

 observations that he has been good enough to communicate 

 on the subject, certainly add greatly to this notice. Thus, I 

 have carefully indicated by the words Ag. Mss. the species I 

 have been able to submit to this able botanist, who has made 

 a special study of the family of Algae. These species have 

 been mentioned by him in the Species Algartun, of which 

 he has published the first volume; but during this period the 

 number of species that I know has been greatly increased, 

 and it is possible, that when careful search has been made in 

 the places where some have already been found, a much larger 

 number may be distinguished. 



I have not spoken in this memoir of the so-called Confervae 

 found in crystals of quartz, not having had occasion to exam- 

 ine them myself; I can do no more than report what authors 

 have said, and I prefer in this case to refer to a memoir pub- 

 lished on this subject by M. J. MacCulloch in the Geological 

 Transactions, t where very good figures will be found. I 

 would remark, how^ever, that if these singular branchings are 

 really the remains of vegetable organisms, they should form 

 a special genus among fossil plants ; one in which we shall 

 be able to place all the fossil confervoid vegetables having 

 articulated filaments. 



In addition to the species observed b}' myself, I am indebted 

 for five figures to M. Schlotheim, given under the names of 

 Alffacitcs crispiforviis, filicoides, graniilatiis, orobiformis and 

 frtimenfarius, in the work already cited ; but among these 

 fossils only the first species I believe may be placed among 

 the plants evidently belonging to the faniil}- of Algae ; the 

 others appear to me to differ so widely from the living Fuci, 

 that I have grouped them at the end with some other doubt- 

 ful .species that I have not cared to place positively in this 

 family. It is easy to see how difficult it is to fix accurately 



*Sur la classifi. et la distri. des Veget. fossiles. Mem. dii Mus., vol. viii. 

 tOn vegetable remains preserved in Chalcedony, by J. MacCulloch, M. D. 

 Trans, of the Geol. Soc, vol. ii, Lond., 1814. p. 510. 



