36 
RECORDS OF THE AUSTRALIAN MUSEUM. 
volume is a paper upon them by Mr. G. Foord, describing the 
enhydros more in detail, and giving an account of the contained 
fluid, which he describes as a dilute solution in water of chlorides 
and sulphates of sodium, magnesium and calcium, together with 
silicic acid. 
Some smaller specimens in my possession have a much more 
regular geometrical form than the three under examination and 
belonging to the Museum. At first sight they might be mistaken 
for crystals, so smooth and regular are their faces, but a very 
little examination shows that this is not the case, practically 
none of the faces are parallel, and their forms do not correspond 
to any crystallographic system. I am inclined to think that 
they have been deposited within cracks and cavities formed 
in the clay (in which they are found), these cavities are probably 
due to the movements of the clay, parts having slid upon one 
another in the process of settlement, and a breccia-like structure 
set up with intermediate gaps and cavities. Mr. Foord’s explana- 
tion that the chalcedony and quartz crystals have been deposited 
upon the walls of the cavities until the entrances to the hollow 
spaces were filled up (a portion of the liquid being thereby 
imprisoned) appears to satisfy the requirements of the case. 
ADDITIONS to the AVIFAUNAS of TASMANIA, and 
NORFOLK and LORD HOWE ISLANDS. 
By Alfred J. North, F.L.S., Assistant in Ornithology. 
During the last twelve months an unusually large number of 
rare or additional grallatorial and natatorial species have been 
obtained in these insular areas. It is my intention here to briefly 
note the latter. Why one season should be better than another 
for aquatic nomads or visitors to make their appearance almost 
simultaneously in places so widely separated as Lord Howe 
Island, Norfolk Island, and Santo in the New Hebrides is prob- 
ably due to exceptionally fine weather and favourable climatic 
adventitious aids conducive to long and extended flight, and not, 
as frequently occurs with arboreal species driven to seek a place 
of refuge, through tempestuous weather. 
