On the Ancient Plant- World. 267 



The Carboniferous period marks an epoch during which a large 

 continental area was from time to time slightly submerged beneath 

 the water, forming vast shallow lakes, whose shores were tenanted 

 by dense masses of vascular Cryptogams and Phanerogamous Gymno- 

 sperms, under a thick atmosphere charged with vapours precipitating 

 rain, with a violence now unknown, producing an equable damp and 

 warm climate. The labours are summarized of Grand'Eury, Eenault, 

 Brongniart, of Corda, Goeppert, Geinitz, Goldenberg, Stur in Ger- 

 many and Austria ; Schimper of Strasbourg ; Lesquereux, Dawson, 

 Dana, in America; and Williamson and Binney in England. 



The Permian flora exhibits transitional and ambiguous characters, 

 the characteristic elements of the Carboniferous being absent — 

 Cycads, Conifers, and some Ferns have the preponderance (Walchia 

 piniformis, Ginkgopliyllum Grasseti). 



In the succeeding Mesophytic, or Secondary epoch, the Triassic flora 

 marks a period of decadence of old types barely replaced by new 

 forms — species and individuals being alike rare. The Conifers are 

 represented by Voltzia heterophylla, Schimp., and Albertia Braunii, 

 Schimp. ; the Ferns by Daneeopsis Marantacea, Hr., and Tceniopteris 

 superba, Sap. 



In the Jurassic epoch, though the Carboniferous types of plants 

 are gone, the Angiosperms, which form nine-tenths of the existing 

 flora, have not yet appeared, except some rare Monocotyledons. 

 Cryptogams are represented by Ferns ; Gymnosperms by Conifers 

 and Cycads, ranging from the Arctic regions to Hindustan and 

 Europe, from Greenland to Irkutsk. Cycads now live in the 

 Tropics, Florida and Japan marking their northern limit. The 

 Infra-Lias Ferns, Clathropteris platypliylla, Goepp., Thinfeldia 

 rotundata, Natk., and Cycads, Podozamites distans, Presl., Ptero- 

 phyllum Jcegeri, Brogn., and Pterozamites comptus, Schimp., in- 

 dicate a damp and humid locality. Ferns also occur in the 

 Corallian, Bathonian, and Kimmeridgian stages. Amongst the 

 Conifers are some resembling the modern Araucaria, others the 

 Cypress. 



Europe, at the commencement of the Jurassic period, formed an 

 archipelago of large islands ; the central plain, at the end of the 

 Lias, was still separated from the Vendee to the west, and from 

 the Vosges and Alps to the north-east. These islands gradually 

 coalescing formed one Continental mass, at 'the close of the Oolitic 

 period, when lacustrine and fluviatile conditions set in, over a large 

 part of England and North Germany, expressed by the Wealden, 

 and Urgonian strata of Wernsdorf, in the Carpathians, which latter 

 has much in common with the Greenland Cretaceous flora. Amongst 

 the latter is the Cycad, Pterophyllmn concinnum, Hr., and Sequoia 

 ambigua, Hr. 



The author comments on the circumstance that led to the 

 appearance and rapid multiplication of Dicotyledons, at the com- 

 mencement of the Cenomanian epoch. He describes the Dakota 

 beds of America as ranging through Kansas, Arkansas, Nebraska, 

 Minnesota, and the region of Missouri, up to the Kocky Mountains, 



