CONCLUSION. 303 



-confidence with which each determination has been made. Many 

 of the extra-British types are undoubtedly specifically identical 

 with Yorkshire species, but in other cases the foreign species may 

 possibly be identical with those from the Yorkshire coast, or they 

 may represent specifically distinct but closely allied types. 



It should be borne in mind, therefore, that the accompanying 

 table is not intended to convey the idea that all the references to 

 the occurrence of Yorkshire plants in foreign localities necessarily 

 imply specific identity ; each record denotes the occurrence of either 

 the same species or a closely allied or representative species. In 

 the lists of plants given in the Introductory section and in the 

 comparisons instituted in the systematic treatment of each species, 

 I have attempted to show how far I regard English species identical 

 with or closely allied to extra-British types. 



In addition to the geogi'aphical regions given in the table, it is 

 worthy of note that some Rha)tic species from South American 

 localities 1 are very similar to English types ; from Madagascar 

 also Zeiller 2 has recently recorded the occurrence of a few species 

 e.g. Klukia (Pecopteris) exilis identical with or nearly related to 

 Inferior Oolite types. 



I propose to consider more fully the stratigraphical correlation 

 of Mesozoic floras in a subsequent volume, but there are some 

 points of geological and botanical interest which should be noticed 

 in reference to the flora with which we are at present concerned. 

 The comparison of the English plants with the Upper Gondwana 

 flora of India and with Australian floras of corresponding geological 

 position, has confirmed me in my opinion that the differences 

 between the Mesozoic vegetation of the Northern and Southern 

 Hemispheres have been exaggerated. Geographical separation of 

 fossil species frequently leads to an unnecessary amount of specific 

 distinction in the naming and determination of plants. "We naturally 

 hesitate to admit specific identity between plants from such widely 

 separated regions as England on the one hand, and India, South 

 Africa, and Australia on the other ; but the too frequent use of 

 distinct generic and specific designations has obscured the botanical 

 resemblances of the Northern and Southern floras. The number 



Vide ante, p. 33 

 3 Zeiller (00 2 ). 



