174 ON REMAINS OF INDIGENOUS WOOD IN ORKNET. 
lidea, and Centrolepidea , are here, as in other parts of extra-tropical 
Australia, in their aggregate more numerous than minute phanero- 
gamic plants in any other part of the globe. A line of demarcation 
for including the main mass of the south-west Australian vegetation 
may almost be drawn from the Murchison River or Shark Bay to the 
western extremity of the Great Bight ; because to these points pene- 
trates the usual* interior-vegetation, which thence ranges to Stmt's 
Creek, to the Burdekin, Darling, and Murray Eiver, while the special 
south-west Australian flora ceases to exist as a whole beyond the 
limits indicated. 
The marine flora of south-west Australia is likewise eminently pro- 
lific in specific forms, perhaps more so than that of any other shore. 
Many of the Alga are endemic, others extend along the whole southern 
coast and Tasmania, where again a host of species proved peculiar; 
some are also extra-Australian. The whole eastern coast contranly, 
and also the northern and the north-western, with the exception of a 
few isolated spots, sueh as Albany Island, contrast with the southern 
coast as singularly poor in Alga. In a work exclusively devoted to 
the elucidation of the marine plants of Australia,— a work which, as 
an ornament of phytographic literature, stands unsurpassed, and which 
necessitated lengthened laborious researches of its illustrious author, 
the late Professor Harvey, here on the spot,— the specific limits ol not 
less than 800 Alga are 'fixed. Some of these are not without their 
particular uses. A few yield carrigeen ; all, bromine and iodine. 
Macrocydis pyrifero, the great kelp, which may be seen floating m 
large masses outside Port Phillip Heads, attains the almost incredible 
length of many hundred feet, while a single plant of the leathery broa 
Urmllea potatorum constitutes a heavy load for a pack-horse. _ 
(To be concluded in next number.) 
ON SUBMARINE FORESTS AND OTHER REMAINS OF 
INDIGENOUS WOOD IN ORKNEY. 
By Dr. William Traill, St. Andrew's. 
{Read before the Botanical Society of Edinburgh.) 
It has long been known that submarine forests exist in dl ^ r ^' 
parts of the English coast: there is one between Liverpool and j 
head, where various bronze and iron articles have been from «» 
