338 



SCIENCE. 



[N. S. Vol. VIII. No. 193. 



micro-organisms is uow one of the most fasci- 

 nating departments of paleobotany. To mention 

 some of these in their systematic order, we have 

 the Coccoliths of the Lias and Cretaceous made 

 known by Sorby and Kothpletz, though their 

 botanical position is doubtful ; the calcareous 

 algai (Schizophyceaj) of various seas, including 

 our Great Salt Lake ; the oolitic grains con- 

 taining calcareous tubes in rocks of various 

 ages, some of which, as, e. g., Girvanella, have 

 been carefully studied and are very ancient 

 (Ordovician) ; numerous forms, parasitic on fos- 

 sil shells and corals, which bore into or through 

 them and have puzzled the paleontologists. 



Fossil bacteria are now well recognized and 

 go back as far as the Devonian. Doubtless they 

 were really coeval with the primal origin of life, 

 if they did not themselves constitute it. 



The old subject of fossil algae, or fucoids (Bilo- 

 bites, Eophyton, Spirophyton, Fucoides, etc, 

 etc.) is disposed of very briefly. As these ob- 

 jects show no internal structure their true na- 

 ture must remain problematical. Most of them 

 are closely imitated by tracks made by various 

 marine animals, and Mr. Seward seems to agree 

 with Nathorstand others in accounting for them 

 in this way. Oldhamia and Dendrophycus are 

 believed to be of mechanical origin. 



Upon fossil diatoms there is now an immense 

 literature and Mr. Seward scarcely more than 

 refers to it. He discredits, however, entirely 

 the claim of Castracane to have found them in 

 the Carboniferous. They are mostly Tertiary, 

 Pleistocene or Plankton. 



Among the green algne (Chlorophycete) in the 

 family Siphoneas there occur some interesting 

 fossil forms. We have here the rare case of a 

 genus founded on extinct forms and subse- 

 quently discovered in the living flora. Such is 

 the genus Acicularia. This case has the addi- 

 tional peculiarity that when first described by 

 D' Archiac it was regarded as an animal. Quite 

 a number of other genera of this group are 

 found chiefly in the Eocene of the Paris basin, 

 but also in older formations, e. g., Cijmopolia, 

 Dactylopora, Qyroporella, Sycidium and Ver- 

 miporella, the last of which is Silurian. Through- 

 out all this the general tendency has been to 

 restore to the vegetable kingdom forms that had 

 been regarded as animal. 



Of red algae (Florideae, Rhodophycete) the 

 principal fossil forms belong to the Nullipores, 

 which form banks resembling coral reefs. The 

 two best known genera are Lilhothamnion and 

 LithophyUum. They are mostly Tertiary or 

 Upper Cretaceous. The genus Selenopora, how- 

 ever, ranges from the Ordovician to the Jurassic. 



To the brown algae (Phaeophyceae) is referred 

 the remarkable Prototaxites of Dawson, a land 

 plant or tree of the Silurian and Devonian, 

 first thought by Sir Wm. Dawson to be conifer- 

 ous, as the name implies, but subsequently 

 found to have nearly the structure of kelp, for 

 which reason, contrary to the rules of nomen- 

 clature, Carruthers changed the name to Nema- 

 tophyms, and still later Dawson and Penhallow 

 proposed to call it Nematophyton, neither of 

 which names can stand. Its history was popu- 

 larly written by Sir William in his Geological 

 History of Plants. 



The fossil fungi are briefly treated with 

 proper reservations and the opinion expressed 

 that Meschinelli's list in the tenth volume of 

 Saccardo's ' Sylloge Fungorum ' ' includes cer- 

 tain species which are of no botanical value. ' * 

 The alleged Carboniferous fungus, Incolaria se- 

 curifortnis, described by H. Herzer from Ohio, 

 in which the mycelia are said to be 'IJ to 2 

 inches in diameter,' certainly did not deserve 

 mention in such a work as this. The occur- 

 rence of fungi as diseases of fossil plants is an. 

 interesting fact and is properly dealt with. 



Mr. Seward erects the Characese into a great 

 group or subkingdom, the Charophyta, coordi- 

 nate with the Thallophyta, Bryophyta, etc. 

 The genus Chara is well known in the fossil 

 state from the occurrence of great numbers of 

 its peculiar so-called 'fruits,' consisting of the 

 calcareous shells enveloping the oospores which 

 always have characteristic spiral markings. 

 Most of them come from the Tertiary, but they 

 are found in the Wealden and the Jurassic, and 

 one form strongly suggesting a Chara was found 

 in Devonian rocks at the Falls of the Ohio and 



* Since the appearance of Mr. Seward's volume 

 Mesohinelli has brought out a fine illustrated volume 

 (Fungorum fossilium omnium huousque oognitorum 

 Iconograplila, XXXI. tabulis exornata,VicetiEe,1898), 

 ■which will furnish a basis for forming a more correct 

 judgment of his work. 



