36 RECORDS OF THE AUSTRALIAN MUSEUM. 



volume is a paper upon them by Mr. G. Foorcl, describing the 

 enhyclros 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 poi^tion 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. 



