ISO 



hydrous oxide of iron, " found in great plenty on the rises on 

 which the previously-mentioned specimens were taken." The 

 marbles are solid throughout, and do not exhibit any signs 

 of having acquired their spherical shape by rolling, particularly 

 as several examples present prominently projecting fragments 

 of quartz. 



Prom the table-lands specimens of chalcedonic quartz and 

 jasper stones " are found scattered about amongst the loose 

 surface quartz on the flats four miles west of this." 



Recent. — Deposits from the springs at Peake. " The surface 

 covering of the flat around the spring " is a fine sand cemented 

 by calcareous matter ; exterior surface of specimen botryoidal. 

 A dense calcareous tuff " from spring flats at Peake." A red 

 ochre with gypsum "found near the springs." A cellular 

 calcareous tuff forms " the top crust of the mound-springs." 

 An opalescent quartz is "a common specimen taken from the 

 springs." 



The above sjjecimens prove most conclusively that the 

 mounds are composed of mineral matter deposited from the 

 water of the springs, and do not owe their form to volcanic 

 action, as is popularly supposed, and has been insisted upon by 

 some observers (see Trans, of this Society, 1879, p. I.) 



Tourmaline. — A large prismatic piece, about 1^ inches 

 diameter, from Mount Boothby, 90 miles north of Alice Springs, 

 where it is said to be abundant. " If I am not mistaken, I 

 have seen plenty of it, only in smaller pieces, running in veins 

 through quartz near the Barrow's Creek Telegraph Station." 

 J. C. 



Mica, in large transparent plates. " In large quantities 

 in the MacDonnell Ranges." J. C. 



Magnetic iron ore, " locality uncertain, but suspected to 

 have been found in this neighbourhood." J. C. 



Sard kaolin clay, " obtained from a high table land hill 

 eight miles south-west from Charlotte "Waters. A quarry of 

 this was opened there, and the station was built of it ; it also 

 makes excellent tobacco pipes." J. C. 



Graphic G-ra:ntte. — Mr. Otto Tepper forwards a specimen 

 of graphic granite consisting of red felspar and translucent 

 quartz arranged prismatically, so that in a cross section the 

 felspar appears to be interspersed with graphic lines of quartz. 

 He writes : — " It was discovered on the north side of the 

 Maitland-road, on the eastern incline of Torke Valley ridge, 

 Torke's Peninsula, forming a dyke of a few yards in width 

 between the gneissic -rock. The strike of the dyke is indistinct, 



