1884.] Age of the Tertiary Basalts of the Atlantic. 19 



Ardtun Read (Mull). 



The specimens exhibited are the result of one day's work. I believe 

 that some of the larger leaves obtained were perfect, but they broke 

 in transit, owing to the brittle nature of the apparently hard matrix. 

 Those previously collected are too fragmentary, and good specimens 

 might easily be obtained by quarrying away the basalt. As the bed 

 is extensive, collections might be made from different spots, and 

 greater variety of plants procured. The leaf-bed is clearly in the 

 track of an ancient river, whose former bed must be exposed in other 

 parts of Mull. 



Ferns. — The only one is abundant, but represented by torn frag- 

 ments, owing to the original tender consistence of the fronds. It is 

 no less plentiful and broken up in some of the Greenland beds, whence 

 it was described by Heer as Hemit elites. This was corrected by Pro- 

 fessor Newberry to Onoclea sensibilis, the only species of a genus now 

 wholly confined to North America. It is unknown from any other 

 locality in Europe. The jointed and striated stems of Equisetum are 

 also abundant. 



Conifers. — A number of short pieces of branchlets have been found 

 at Mull by Mr. Koch, and at Canna, which cannot be distinguished 

 from the Ballypalady Cryptomeria. Linear leaves, possibly of 

 Sciadopitys or an Abies, are rarer. The specimen originally figured 

 by Edward Forbes as Taxites Gamplelli still remains unique, though, 

 said by Lyell to be the most abundant conifer. It was claimed by 

 Heer as Sequoia Langsdorfi, and was one of the three species which led 

 him to consider the deposit to be of Miocene age. It is a coniferous 

 branchlet with distichous foliage, and without definite generic cha- 

 racter. Similar foliage from Disco has also been determined to be 

 the same species, but on what basis is not apparent. Plenty of 

 distichous foliage, but of different type, has been found at Mackenzie 

 River and Spitzbergen, but it hardly follows that because these were 

 referable to Sequoia, all distichous foliage must be equally so. The 

 genera Taxus and Taxites have been almost expunged from lists of 

 Tertiary fossils, yet the extreme antiquity of Taxus cannot be doubted, 

 and there is no reason to exclude it from Tertiary floras, for it has a 

 wide distribution now and many species. Sequoia forms considerable 

 groves, and where met with fossil, occurs in abundance ; but the Yew 

 is solitary, and while the fruits of the former, if associated, could 

 not escape detection, the berries of the latter might easily be over- 

 looked. 



Monocotyledons. — There is the usual proportion of reeds and rushes 

 inseparable from plant-beds formed by river- side. 



Dicotyledons. — The upper part of the bed is choked with large 

 leaves of a roughly palmate form, seemingly to the exclusion of all 



