918 



SCIENCE. 



[N. S. Vol. XX. No. 522. 



The bulk of the volume is naturally devoted 

 to a detailed treatment of the material in the 

 British Museum, in which the museum num- 

 ber of every specimen is recorded. But the 

 * catalogue ' becomes, at the hands of Mr. 

 Seward, a systematic treatment of the flora, 

 which attains great importance from the adop- 

 tion of the latest botanical classification. The 

 Jurassic flora is thus found to embrace Bryo- 

 phyta (Hepaticse), Pteridophyta (Equisetales, 

 Lycopodiales, Filicales) and Spermatophyta 

 (Cycadales, Ginkgoales, Finales). The evi- 

 dence for the alleged existence of algas (fu- 

 coids) is examined and found wanting, such 

 forms being either referred to the genus Mar- 

 chantUes of the Hepaticse, or rejected as prob- 

 ably not organic. Of these the Cycadales 

 predominate even over the ferns, which latter 

 contribute the largest contingent to the Weal- 

 den flora, the conifers occupying the third 

 place in both floras, and the lower groups a 

 very subordinate position. The total Jurassic 

 flora counts 55 species, as against 59 from the 

 Wealden, which contains many more conifers. 

 Every important specimen is fully treated and 

 usually figured either in the text or on one of 

 the twelve plates. Proofs of these plates had 

 been received in advance of the text at the 

 time of my visit to Cambridge, in 1900, and 

 Mr. Seward kindly permitted me to examine 

 them and take notes upon them for use in 

 preparing my paper on the Jurassic flora of 

 Buck Mountain, Oregon, which I had recently 

 collected, and later he had the further kind- 

 ness to send a set of them at my request to 

 Professor Fontaine to aid him in his elabora- 

 tion of that flora. They were of great assist- 

 ance, although, as might have been expected, 

 very few species are common to the two floras. 

 The work in which the Oregon Jurassic flora 

 is treated is now in press. 



In the second part, which has recently ap- 

 peared, dealing with the remainder of the 

 Mesozoie floras of Great Britain, the treat- 

 ment follows the same lines, but there is no 

 extended introductory survey of the corre- 

 sponding floras of other countries. The classi- 

 fication, however, is here primarily geological, 

 each horizon being treated systematically. 

 Scarcely any Triassic plant-bearing beds exist 



in Britain, and the only plants of that age 

 seem to consist of a few indistinct and prac- 

 tically indeterminable specimens from the 

 Keuper beds of Bromsgrove and Pendock in 

 Worcestershire and from Eowington in War- 

 wickshire. A few specimens from both these 

 localities occur in the museum, but only onf, 

 fruit (Carpolithes) could be even generically 

 determined. 



The Ehetic is included by Mr. Seward in 

 the Jurassic, but it is very limited in Britain 

 and no such rich plant-bearing beds of it occur 

 as those of south Sweden and Franconia. But 

 there is a thin belt of this age extending from 

 the Yorkshire coast to the cliffs of "Dorset- 

 shire, and they are also found near Carlisle 

 and in the northeast of Ireland and north of 

 Scotland. Fossil plants have been found at 

 Ashelworth and Broekeridge; in the East 

 Somerset and Bristol coalfields; at Pylle Hill, 

 Totterdown and Bristol; at Strensham, Wor- 

 cestershire; and at Binton, Warwickshire. 

 Only three species are described from the 

 material in the British Museum. These are 

 all pteridophytes, but a winged seed (Carpo- 

 lithes) and an imperfectly preserved cone 

 (f Araucarites) occur, which are probably 

 gymnosperms. The supposed monocotyledon 

 (Naiadita) figured by Buckman, proves to be 

 a lycopod, and the dicotyledonous wood de- 

 scribed by Sorby, upon which Dr. Asa Gray 

 laid so much stress as proof of the antiquity 

 of the higher plants, is stated to have been 

 purchased of a dealer, the locality (Lias of 

 Keynsham, near Bristol) being only conjec- 

 tural. 



The Liassic fiora is much better represented. 

 This formation stretches across England from 

 the mouth of the Tees to the coast of Dorset- 

 shire, with patches in Shropshire, Cumberland 

 and Sutherlandshire, as well as in the west 

 of Scotland and on the Antrim coast in Ire- 

 land. Among the important localities for 

 plants of this age are Lyme Regis, Memburg 

 and Polden, in the southern section, and 

 Whitby on the Yorkshire coast. There are 

 also Liassic plant beds in the interior of Eng- 

 land. The great majority of the specimens 

 in the British Museum 'are from Lyme Eegis 

 and Whitby, especially the former. The flora 



