Hawell : An Oolitic Plant Bed in North Cleveland. 315 



nothing- to show whether it belong-s to one or other of the two 

 subdivisions Cycadales or Benncttitales. 



Of the g'enus Dictyosamites only two species were previously 

 known, Dictyosamites falcatus from the Rajmahal series of 

 India, and D. Johnstrupi from Bornholm. Of D. fulcatiis two 

 varieties, var. distans and var. gyossineiins, have been recorded 

 from Central Japan. The cropping- up of this g-enus in rocks of 

 approximately the same ag^e in areas of the earth so widely 

 sundered is of extreme interest. Mr. Seward in his very 

 valuable and sugg-estive paper shows how this Lower Oolitic 

 flora as a whole has a remarkable similarity of character over a 

 g-reat portion of the world's surface, a fact which had not 

 previously been at all adequately realised, in g-reat measure 

 owing- to the circumstance that the same g-enera and species, or 

 g-enera and species most closely related, have in different reg'ions 

 received entirely different names. 



This world-wide sameness of the Jurassic flora is in strong- 

 contrast not merely with the wide differences between the 

 veg-etation existing- in diff'erent parts of the world during; the 

 Tertiary epoch, but also with the like state of thing-s existing; 

 during; Palceozoic time. It is even possible to trace the orig-in 

 of this Jurassic flora to the Permo-Carboniferous Glossopteris- 

 flora of the Southern Hemisphere, while the orig;in of the 

 Tertiary and recent floras are at present entirely untraceable. 



I have presented the two fig;ured specimens of Dictyosamites 

 Haiaelli to the South Kensing-ton Museum, but very recently 

 I have obtained from Marske a specimen of the species which is 

 in most respects better than the figured types. In developing- 

 this I came upon a specimen of Ginkgo digitata — the first 

 example of that species which has occurred to me. To develop 

 the Dictyozamiies farther would be to destroy this interesting- 

 specimen, and therefore I propose to leave it as it is until I come 

 upon another specimen of the Ginkgo. 



The species which I have so far identified from Marske — 

 with the help of Mr. Seward — are the following- : — Tceniopteris 

 vittata Brong-., T. major L.&H., Williamsonia gigas L.&H., 

 W. Pecten Phill., Nilssonia teniiinervis Nath., N. rnediana Leek., 

 A^. conipta Phill., Dictyosamites Haivelli Seward, Sageiiopteris 

 Phillipsi Brong-t. var. major Seward, Otosamites Feisimanieli 

 Zig-no, O. parellelus Phill., Equisetites colmnnai-is Brong., 

 Cladophlehis denticnlata Brong-., Ginkgo digitata Brong., 

 Gymyiosperm Seed (Beania ?). There are probably one or two 

 others which are so far undeterminable. 



1903 August I. 



