84 
Specimens of the Mull deposit were exhibited under the micro- 
Scope, as well as specimens of the deposit in its natural state, and of 
the polishing powder obtained from it. 
Desmarestia Dresnayi on the Coast of Ireland. 
“On the occurrence of Desmarestia Dresnayi on the Coast of Ire- 
land ;’ by W. Sawers, Esq., Londonderry. Communicated by Dr. 
Greville. 
In a letter to Professor Balfour, Mr. Sawers stated, “I have great 
pleasure in sending you specimens of an Alga, new to the shores of 
the United Kingdom. Specimens having been sent to Dr. Montagne of 
Paris, Member of the French Institute, by Dr. Landsborough and the 
Rev. M. J. Berkeley, Dr. Montagne writes, that he gathered the same 
plant at Fort St. Sebastian, Spain, in 1823, and published a descrip- 
tion of it, with a plate, in 1842, in the ‘ Annales des Sciences Natu- 
relles,’ naming it Desmarestia pinnatinervia, and that it has been got 
by M. Crouan, at Brest, though rarely. Crouan makes it a variety of 
Desmarestia Dresnayi, but Montagne maintains the distinctness of his 
species, and retains his name D. pinnatinervia. I got the young 
fronds floating early in August at Molville, near the mouth of Loch 
Foyle, and have visited the locality frequently since, always getting a 
number of specimens, the great majority imperfect, being eaten by 
mollusks, &. When fresh, it has the colour of a Laminaria, but is 
not so glutinous to the feel, and thinner. The root is a disk, and 
sometimes two or three fronds arise from the same disk; in some 
cases they are slightly proliferous where the margin has been injured. 
The frond is from 12 to 18 inches long, and 2 to 4 inches in breadth. 
The lateral nervelets are forked as in the frond of a fern.” 
Dr. Greville was of opinion that the plant must be referred to D. 
Dresnayi. He read a description of it, and exhibited a drawing, 
both of which will appear in the Society’s ‘ Transactions.’ 
Flora of the Vosges. 
“ Remarks on the Flora of the Vosges ;’ by Dr. Dubuc. 
Dr. Dubuc presented a parcel of plants received from Dr. Mougeot, 
to which his remarks had reference. He stated that the principal 
mountains of the Vosges were about 120 miles in extent, and run 
parallel to the Rhine, consisting chiefly of dome-shaped swelling hills, 
turfed on the top. Formerly they abounded in forests, but many of 
them are now bare. The highest summit of the Vosges does not 
exceed 4693 feet; their tops are generally formed of red and gray 
