4 6 SCIENCE PROGRESS. 



their nomenclature as they are dubious in botanical char- 

 acter. 



The most hopeful direction for work then appears to be 

 in the search for further encrusted Algae, for more coral- 

 lines, Udotece, for diatoms in the older rocks and perhaps for 

 other FloridecB such as Squamariaceee of which no record 

 has yet been obtained, though the thallus has an equal 

 chance with some of those mentioned. The Cretaceous 

 seas had a plant Plankton like our own in the matter of 

 diatoms and Coccospheres and Rhabdospheres and the older 

 Secondary rocks may yet prove productive of more and 

 better defined forms. The example of Munier-Chalmas is 

 inspiriting, and by following it the great periods laid waste 

 by the successful destructive criticism of Nathorst and 

 others may yet be re-peopled with forms having valid 

 claims to recognition as true fossil Algae. 



BIBLIOGRAPHY. 



(i) NATHORST. Memoire sur quelques traces d'animaux sans 

 vertebres, etc., et de leur portee palaeontologique. Kongl. 

 Sveusk. Vetenskaps Akad. Hand/., bd. xviii., No. 7, 1S81 

 (with bibliography). 



(2) NATHORST. Nouvelles observations sur des traces animaux. 



Ibid., bd. xxi., No. 14, 1886. 



(3) SAPORTA. A Propos des Algues Fossiles. Paris, Masson, 1882. 



(4) CARRUTHERS. On the History, Histological Structure and 



Affinities of Nematophycus Logani, an Alga of Devonian age. 

 Monthly Micr. Journ., vol. viii., 1872. 



(5) CARRUTHERS. Nematophycus or Prototaxites ? Ibid., vol. 



x., 1873. 



(6) BERTRAND and RENAULT. Pila bibractensis. Bull, de la 



Soc. d'Hist. Nat. Autun, 1892. 



(7) SOLMS-LAUBACH. Fossil Botany. Oxford, Clarendon Press. 



(8) Zittel. Handbuch der Palceontologic, II. AbtJi. Palatophyto- 



logie, commenced by Schimper and completed by Schenk, 

 1879-90. 



(9) MURRAY. On a fossil Alga belonging to the genus Caulerpa 



from the Oolite. Phycological Memoirs, i., 1892. 

 (10) SEWARD. Catalogue of the Mcsozoic Plants in the Depart- 

 ment of Geology, British Museum {Natural History). The 

 Wealden Flora, part i. London, 1894. 



