PRE-CAEBONIFEROUS FLOKAS. 



443 



fication. Under the former supposition, they may be compared with 

 Annularia laxa of the Devonian, and the radiating root - like bodies 

 associated with it. — (Dawson, Eeport on Devonian Flora.) Under the 

 supposition that the plants are Algse, they may be compared with Sphcero- 

 coccites Schurtzanus of Goeppert, from the Silurian (Etage D.) of Bohemia, 

 though they do not come under the technical definition of Sternberg's 

 genus Splicer ococcites. 



Whether or not either of the above he truly referable to 

 land-plants, Professor Leo Lesquereux has recently described 

 from deposits of Lower Silurian age 

 (Cincinnati Group), in North America, 

 remains of a plant which he considers 

 to be referable to a Sigillarioid, and 

 therefore to be undoubtedly terrestrial. 

 These remains he has referred to a 

 special genus under the name of Pro- 

 tostigma ; and if his determination be 

 correct, we have here not only the 

 most ancient undoubted land -plants 

 known, but also the proof that even 

 at this early period the terrestrial 

 vegetation was of anything but a low 

 order ; since the Sigillarioids — wher- 

 ever they may be ultimately placed — 

 are unquestionably highly specialised types. 



In the Upper Silurian rocks are also numerous remains of 

 " Fucoids " {Artliroipliycus, Diduolites, Chondrites, SpirophTjton, 

 &c.), which do not differ in any important point from those 

 of the inferior division. Some of these can hardly be any- 

 thing but true plants, and would certainly seem to be the 

 remains of genuine Sea- weeds. Besides these, in many cases, 

 problematical fossils, however, the UjDper Silurian rocks have 

 been shown to contain the remains of genuine land-plants. 

 Thus, remains of the Lycopodiaceous genus Lcpidodendron 

 {Sagenaria) have been discovered in the Upper Silurian of 

 Germany and Bohemia. At the summit of the Upper Silu- 

 rian series in Britain have been detected numerous seed- 

 vessels or " sporangia " referred by Hooker to a Lycopodia- 

 ceous plant under the generic title of Pachytheca. Lastly, 



Fig. 698.— A small slal> with 

 one of the whorls of Butho- 

 trephis (?) radiaUis upon it, of 

 the natural size. Lower Silu- 

 rian (Skiddaw Slates) of tlie 

 North of England. (Original. 



